Though one’s now starring in a drama, the other in a comedy, Lizzy Caplan (“Masters of Sex”) and Allison Janney (“Mom”) have both famously spent time in the other category — and agree that the lines are now getting blurred. Their back-and-forth banter at Variety’s “Actors on Actors” studio proved the point, as the actresses chatted about the thrill of doing theater, and the emotional toll of getting into character.

Lizzy Caplan: I was wondering what your first job on television was.

Allison Janney: It was a small teeny role on a Bill Cosby show.

Caplan: Stop.

Janney: I’m not kidding you!

Caplan: Did he give you any…

Janney: Nothing untoward happened! He wanted me to play a janitor and then I was a school teacher. He kept changing what my part was. I don’t remember what the show was called. And that was my first TV show! What was yours?

Caplan: I’m so glad you asked. My first TV show was “Freaks and Geeks.” Which is a very cool first show. I only had one line and I wasn’t good, bad or anything in it. I was just scared to be there.

Janney: What was your one line?

Caplan: My one line was, “I can’t go to the dance with you. I’m going with someone else.” And I think I said it about ten billion times in my trailer.

Janney: Oh my god, that’s a cool first TV experience.

Caplan: It wasn’t cool in the moment but it has paid cool dividends since, for sure. It’s great cred to have been a part of that show even though I made no impact whatsoever.

Janney: The second television show I did which was a little cooler than the Bill Cosby show was a show called “Morton and Hayes.” It was done by Christopher Guest and Michael McKean and Rob Reiner and all the guys from “Spinal Tap.”

Caplan: That’s amazing! Is it a great show?

Janney: Well, we aired like six episodes, and it was done in black and white. And I think all of America was like, what’s wrong with my TV? But it was fantastic getting to work with them.

Caplan: Were you improv-ing the whole thing?

Janney: No. Do you improv? Are you a good improvisational actress?

Caplan: I’m not a trained improvisational actress.

Janney: I’m not, either.

Caplan: But you’re good.

Janney: I’m not comfortable doing it but at the end of a scene if they keep the cameras rolling sometimes I’ll throw something in there and see if it gets in.

Caplan: I find it’s easier if you’re with amazing improvisational actors. Because I just react to what they’re doing.

Janney: I just worked with Melissa McCarthy, who is the queen of that. And literally I just sat across from her and just listened. I love having lines to memorize and knowing what I get to say because in real life I feel like I don’t converse well. I don’t like to talk at all.

Caplan: They probably don’t let you improv at all on “Mom.”

Janney: No.

Caplan: I remember doing a show like that and it’s a musical score almost.

Janney: Yes, it is very much. Chuck Lorre is a musician, he writes with that ear, that sense of rhythm and if you add another word to it, they make you go back. It’s just like Aaron Sorkin, who wrote “West Wing.” You had to get it letter perfect.

Caplan: So you must be really good at that. I have a really hard time with that.

Janney: I feel like I’ve used up my memorizing chip. I’m actually terrified to get back on the stage. Did you ever do stage?

Caplan: Never.

Janney: You have not done the stage?!

Caplan: No, and I really want to, it’s so intimidating.

Janney: Lizzy, you have to do it!

Caplan: It’s completely different than anything you could do in film, and I’m embarrassed that I haven’t done that.

Janney: Honey, I think you would love it, just because it’s for one hour, or however long the play is. You’re get to go through the whole thing without someone saying, “Cut.”

Caplan: But that’s so scary! You have to know the whole thing. That seems impossible. To know the whole thing.

Janney: You could do it. Some people get bored having to do it over and over again. It does get a little monotonous, but I pretend that it’s Groundhog Day, and if I do it right tonight, I won’t have to do it again. So it gives me a reason to get excited about saying the same damn thing. I trick myself, I’m easy to fool.

Caplan: But the audience too changes it, that’s what everybody I know who does theater says. So every night it feels like a completely new thing.

Janney: You’ve had an unbelievable emotional journey on that show as Virginia. What was the most challenging moment for you last season?

Caplan: One is the naked thing which I hate saying because it hasn’t been the case up until this moment. I find that to be a lot less intimidating than the other stuff they make us do, which is the emotionally taxing stuff. In he fight episode with Michael Sheen in the hotel room, there’s this one moment where he takes my robe off and I have to stand there completely naked and then begin masturbating to completion just standing there, naked. That was not my favorite day. Doing it was not terrible or traumatic in any way, it was more the moments in my trailer leading up to going out there and doing it. I haven’t really had the feeling of wanting to get the fuck out of there, and I wanted to get in my car and just keep driving. I just didn’t want to do it.

Janney: Who was directing that episode?

Caplan: Michael Apted.

Janney: The safest, loveliest man on the planet.

Caplan: So I got to do it in a way that I felt good about how I did it because it wasn’t at all for the male gaze in the least. It was a power move, and it was really quiet and really subdued to the point that Michael Apted came up to me afterwards and said, “I wasn’t sure that you’d come.”

Janney: Did you fake it?

Caplan: No, no. I fully masturbated and had an authentic orgasm, thank you for asking.

Janney: [Laughs.]

Caplan: The truly most difficult was halfway through the season when Julianne Nicholson’s character passes away. That was very, very brutal. She dies of cancer, which brought back a lot of stuff from my own childhood in a way that I hadn’t experienced before. And I know that’s one of the greatest and most challenging things about being an actress is you relive past trauma. My mother had passed away from cancer when I was a kid. There’s something about Julianne that reminds me of my mother. I was grateful to have gone through it, but that was not a fun week. She and I would just see each other in the makeup (trailer) and start crying. It was awful.

Janney: How do you get yourself in a place to do an emotional scene?

Caplan: I find that it’s easier to do it, the second season of the show, because they put Virginia through so much emotional stuff. It was yet another muscle that getting worked over and over again and so I didn’t have as much trouble going to those places. Also, in shooting the second season I didn’t do anything except go to work and go home and go to sleep. I may as well have been in another country. I do find that it probably would have been possible to find a little bit more balance, but I wasn’t interested in it, I wanted to be fully immersed in it, and so I was just kind of sad all the time. And so it was easy to get sad on set, because my life was not particularly joyful anyway that second season. How do you do it?

Janney: I do different things. I love to listen to music. It puts me in a place where you know it’s hard when, when I have to be emotional about something that I have no connection to at all. I went to the neighborhood playhouse where they teach you emotional preparation where you listen to music and just imagine something awful happening. When I did “View From The Bridge” on Broadway and I had to cry every night, I would just take the bus and watch people out on the street, because that would make me cry, just watching. In New York, there’s so many people out there and you don’t know what their stories are. You see some homeless man and I started thinking about what he was like as a little boy. Anything to just get in touch with your human side. I think I probably would have been a happier person had I not chosen to be an actor.

Caplan: I’ve been thinking about that a lot, because that stuff makes me sad all the time. I can’t go through a toll booth without crying over what the toll booth operator does for Thanksgiving. They probably have a great Thanksgiving, but in my mind it’s a very sad, depressing Thanksgiving. Because it’s your job to really mine the emotional depths of a person that’s not you. But I find it impossible for that not to bleed over into your real life and who you are as a person so you just end up feeling things.

Janney: I find it easier to let go than it used to be, but if I went on stage and I didn’t have the emotion I needed for a scene, I would feel like I was a doctor and I lost a patient on an operating table. And I’d just hate myself until the next performance. The hating myself so much made me cry. I just beat myself up so much. It’s just a crazy thing we do.

Caplan: It’s awful. When you were doing the play where you had to cry every night, was there any part of you that wanted to go out afterwards and have a good time?

Janney: Oh my god, yes. The curtain would come down at 11 or 11:30, from that point on until I went to bed was when my day started. Everyone in the theater loves to go out to dinner afterwards.

Caplan: That seems romantic.

Janney: I wanted to ask you about playing a real person. Virginia Johnson died right before the show premiered?

Caplan: She passed away after we shot the pilot. But she made it very clear that she didn’t want any involvement in it whatsoever.

Janney: When I have to play someone real, I have to do a lot of research. What kind of research did you do for it?

Caplan: I always wonder if I could have done more but she was such a secretive person, both of them were, that really the book that our show is based on, that was the first time she opened up publicly about what was going on. And it was her account as an 80-something yea- old woman. And at that point she was bitter, justifiably, about certain things, and so you have to read it with a grain of salt. When I first read it, I was like this is the truth, this is what happened. But as I started to get to know her more, I feel she was going through a depressing end of her life.

Janney: Does that help you as an actress?

Caplan: It does. I really wanted to meet her. I wrote her a very long letter but she never replied. She made it very clear to the people involved that she just wasn’t interested.

Janney: She wasn’t happy with it? She didn’t want her story to be told?

Caplan: I don’t think she read the script, it was more that she wrote this book, and that was her story, and then she wanted to just live out the rest of her life away from it all. Which I had to respect, but it drove me a bit crazy. And I’m also not tasked with doing a direct impersonation, because people don’t know what she sounds like or how she moved or anything. Which is good, because I don’t know if I would be any good at that.

Janney: I get very nervous about doing anyone that’s a historical figure. I was asked to play Eleanor Roosevelt. And I was like nope!

Caplan: Allison, you’ve done “The West Wing,” a dramatic show, and you won ten million awards and you were amazing in it. And now you’re doing comedy. Which do you prefer? How was that transition?

Janney: I definitely think “Mom” is a comedy, although we do deal with subject matters that aren’t funny and and we manage to make them funny but also deal with things that happen in real life. I lose the man in my life who I love and I have very emotional moments I have to do that that rival any emotional work I’ve ever done. It’s the same acting, it’s not different. I know I’m going for laughs but I think “Masters of Sex” it’s just, everything. I think things that are great are things that have it all in there.

Caplan: Wow. Totally.

Janney: One of my favorite scenes was the interview scene with you which was so beautifully written, but the humor in it was there. When I realize I haven’t had an orgasm before and I go, “Well, I’m a quick study, I taught myself Italian.” I mean, that stuff makes me laugh. Or when the prostitute says, “What is your husband into?” and I say “the opera and Salisbury steak.” That’s so funny to me. The thing that is different about “Mom” is that it’s the half-hour format. It’s a great job, it’s a great schedule, and you get to perform in front of a live audience, which I’d never done before. I really just wanted to try it. It’s a regular job where you get to go home at night and see your family or see friends, have dinner. It’s a luxury.

Caplan: I think you’re right, I think that the best stuff has elements of both. That’s the kind of stuff that I gravitate towards. Next question. Given the choice, would you rather have a dream vacation or a dream job?

Janney: Well, it would have to be dream job.

Caplan: It’s always dream job.

Janney: I can take a vacation later.

Caplan: I know but that’s the problem, there’s no later. It never happens.

Janney: I feel like I just have to make hay while the sun shines.

Caplan: What is that from, that inherent fear that if you don’t keep moving then it’s all going to go away? You still have that?

Janney: I do. Absolutely. That’s what I have to do. I don’t kids, I don’t have a husband.

Caplan: You know, I heard that they put some stuff in that Emmy basket.

Janney: There’s a trip to Bora Bora. I want to go to Bora Bora.

Caplan: That sounds amazing! Those huts with the glass.

Janney: Maybe I’ll take you to Bora Bora with me.

Caplan: Allison, let’s just go to Bora Bora and tweet!

Janney: That sounds fantastic.