If you tuned into FX’s “The Comedians” Thursday night, there’s a good chance you’re glad Billy Crystal is back on television. Showrunner Ben Wexler shares that same sentiment.

“At my sister’s Bat Mitzvah when I was 14, I emceed her Bat Mitzvah, and I mostly did Billy Crystal impressions,” Wexler, who live-tweeted the show’s premiere, tells Variety. “Literally, you could count on less than one hand the (number) of people that made me want to do this for a living, and he’s probably the thumb. To be on a first-name basis with the guy is a thrill and a dream come true.”

However, it’s not just Crystal who impresses Wexler.

The exec producer, who co-created the FX comedy with Larry Charles and Matt Nix, says co-star Josh Gad, 33 years Crystal’s junior, is so funny that he and Crystal are both probably part of an imagined comedy club that comics are welcomed into when they’ve reached “a certain level of funny.”

“They’re hall of famers. They’re comedic geniuses, those two,” Wexler raves. “This has been the most gratifying experience of my career by far, and it’s also been incredibly exciting and incredibly fun. It’s really, really hard, but at the end of the day, it’s actually really simple because it’s just funny people being funny. When you give people who are genuinely hilarious the opportunity to be hilarious, it works.”

Wexler gives Variety a behind-the-scenes account of working with “The Comedians” on set:

How do you describe working with your idol, Billy Crystal?

To hear that this is one of the best creative experiences he’s ever had, to have his manager tell me how happy is, to have his wife come up to me and tell me how happy he is at the end of every day, it’s beyond description how satisfying that is. Sometime this magic happens and it works, and I have no doubt that’s what’s happening. It feels like magic. It feels like something that only comes along once.

Was it difficult to work with two pros who go off script and are improvising on set?

It makes my job so much easier knowing that what’s on the page, they’re going to nail, and then, they’ll almost certainly add to what’s on the page. You’ve got people who are incredibly quick on their feet and are really nimble, and that shows up onscreen. The de facto product of having guys who can improvise, it’s sort of like having more writers.

Were you just cracking up non-stop on set?

So much so that I literally slid out of my director’s chair at one point, and spent the last half of a scene crouched on my knees just trying desperately not to laugh loud enough to break the take. We shot for 48 days, and I’m not sure there was a single day that I didn’t truly belly laugh and, sometimes, to the point of tears.

Billy told us that Josh barely breaks character. True?

They both do! It’s actually really fun when it happens. It’s been the comic basis of blooper reels, since time began. I’m probably more impressed by their ability to stay in a scene long, long, long past the point at which I’d be dissolved in a puddle of tear laughter. It’s a special skill. There are little moments where you can see Billy’s lips start to quiver, and in the editing room, I’ll give him sh-t, and he’s like, ‘Oh yeah.’ It’s fun to watch.

Did you think Billy and Josh would work this well together?

From the minute Josh walked in the room the first time we met him, we all turned to each other and we’re like, ‘We’re done.’ Nothing has surprised me on this show, in terms of how well it works. When you have guys that are that good, why shouldn’t it work?

How would you describe Billy and Josh’s relationship off camera?

Weirdly parallel to what you see onscreen. They really, really love each other, and it’s not without tension. The fact of the matter is no two comics have the exact same style of comedy. There really is a generational difference. Josh just grew up watching different stuff that Billy grew up watching, and I think that informs their differences, and so, we really not only try to embrace that, but we need to embrace that because it’s what our show is. Watching the two of them, it seems like guys who have known each other a lot longer than a year. There’s a real comfort there, and then, they really love tweaking each other and they love doing it on camera. It’s just fun.

Is there a father/son relationship at all between the two of them?

In real life, I think it’s more of a friend relationship. In the show, there’s a weird father/son thing going on and in a way, that forms the backbone of the arc of our season. To me, that’s really interesting to portray dramatically.

This is very different than other comedies on TV right now. Why do you think it will fit well into the television landscape?

All I can do is hope it fits well in the TV comedy landscape. Your goal is to fit into the comedy landscape and also to not fit into it. I think that the shows that transcend, there is no sister show like it. Humbly, I think this is that.