Julianne Hough is a live-TV pro, thanks to “Dancing With the Stars,” but nothing could prepare her for the pressure of playing Sandy to Aaron Tveit’s Danny in Fox’s “Grease Live” musical event. “It’s a little daunting,” she says, “especially because Olivia Newton-John and John Travolta have completely made these roles iconic.”

Is it safe to assume you’re a longtime “Grease” fan?

Oh my gosh. It’s kind of like how kids know Michael Jackson and Mickey Mouse and Elvis. You just know “Grease.” When I was a kid, my parents wouldn’t let us watch the PG-13 movies. When they were gone … I’d go downstairs to the basement and put on “Grease.” I’d do the dances and songs and try to be Sandy as long as I could — until the dance scene, and then I went into full-blown Cha Cha.

What has the general reception been to your casting? 

I’ve had overflowing love and support from everyone, including Olivia Newton-John. I met her, and she was like, “Oh, you’re a perfect Sandy!” That took some weight off my shoulders a little bit.

How will this version of “Grease” differ from the original — or will it stay true to the classic?

We’re using a combination of both the Broadway production and the film version. I think we’re leaning a little bit more towards the film version, and taking some songs from the Broadway show. We don’t want it to come across as Sandy’s going to change for [Danny] and turn into this bad girl and then he’s going to like her. We’re trying to portray that she’s kind of just figuring out who she is on this whole year-long journey that they’re in high school. And then the same thing with Danny — he’s kind of growing out of having to be the cool dude, but he’s still not sure how he can do that and still be friends with those guys. It’s more about discovering ourselves for ourselves, rather than changing for someone.

“Grease” is the first of the recent TV musicals to incorporate a live audience. What type of energy does that add?

I think there are different kinds of performers, and I’m the kind who thrives off the adrenaline and the pressure that something could go wrong … We give 100% in all of our rehearsals, but then that extra little 15% comes from the audience.

What is your favorite “Grease” song?

Oh my gosh — that’s like asking me what my favorite dog is! I love “Summer Nights” because that’s kind of the introduction of Danny and Sandy … To sing, I love singing “Hopelessly Devoted.” We’ve moved where “Hopelessly Devoted” was in the movie and put it a little bit later so you can really see [Sandy’s] struggle of like, “Ugh, he’s like this, but I’m so in love with him and I have no options. I’m hopelessly devoted to him.” So I love singing that, and then one of my favorite songs is Rizzo’s “There Are Worse Things.” If you listen to those words it’s so heartbreaking and Vanessa [Hudgens] kills it. In rehearsals we’re all just sobbing. She nails it, she’s so good.

Are the costumes modernized or are they truly old-fashioned?

It was kind of interesting when “Grease” came out in 1978, it was ‘50s with an ‘80s take on it. Ours is true ‘50s. Maybe our shirts are tailored a little bit more and our waists are a little bit more taken in for our era. Maybe our skirts are an inch shorter. There are certain things that maybe feel a little bit more modern, it won’t look it though because we’re so used to that.

What makes Vanessa so perfect for the role of Rizzo?

Well, everybody’s saying I’m the perfect Sandy — well, that girl is a perfect Rizzo. I couldn’t think of a better character and role for her to really showcase what she can do. The first day of rehearsal we came in, she was so prepared and so on it. She just already embodied the character. They were doing “Freddy My Love,” just marking it, and we were standing there and Zach Woodlee, our choreographer, goes, “She looks like she’s gonna eat somebody!” Her raw sexuality as Rizzo is so good.  

And what makes Aaron the perfect Danny?

Aaron is amazing. He came from the musical theater world. He’s such a pro. He kinds of grounds us and makes us feel really weighted. 

Some rumors are swirling: Any chance Olivia could make a cameo during the event?

I have not heard that, but if that’s going to happen, I might cry — and it is live television.