Fox is hoping to fend off winter ratings chill with some sexy “Summer Nights’’ as the network turns over its Sunday prime-time block to “Grease: Live,’’ a new production of the 1950s-style hit Broadway musical premiering Sunday at 7 p.m.

In roles made famous by John Travolta and Olivia Newton-John in a blockbuster 1978 film adaptation of the show, Aaron Tveit (“Graceland’’) and Julianne Hough (“Dancing With the Stars’’) lead the cast as Rydell High School lovers Danny Zuko and Sandy Dumbrowski. Vanessa Hudgens, who knows a thing or two about high school musicals, is bad girl Betty Rizzo, and the cast also includes Carly Rae Jepsen, Keke Palmer, Carlos PenaVega, Mario Lopez and Ana Gasteyer.

Tveit, 32, says playing his iconic role feels a bit unreal.

“I think ‘Grease’ is really the first musical that I was aware of in my life, even before I knew what a musical was,” he says. “I remember watching it as a little kid, 6 or 7 years old. It’s so woven into our cultural zeitgeist that I knew of it even before I understood what it was to be in a play.

“When we started rehearsing and moving around for ‘Summer Nights’ and ‘You’re the One That I Want,’ those are the kind of moments where part of you stops and thinks, ‘Wow, I’m really doing this now!’ Stepping back and watching yourself perform them is kind of surreal.”

Unlike NBC’s live musical productions, most recently December’s “The Wiz Live!,’’ this Fox special will be performed in front of an audience, a decision that was a no-brainer, director Thomas Kail says.

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“It just always felt like the nature of this show’s rhythms, and musical comedy in general, necessitated having an audience,’’ explains Kail, who earned a Tony Award nomination for directing the Broadway hit “In the Heights.’’ “We wanted to feel the energy boost from the ‘conversation’ that happens between an audience member and a performer, and to let the audience at home participate in that.’’

‘‘Grease: Live’’ borrows from both the movie and the original stage musical, he adds.

“Our script takes a lot of inspiration from the spine of the movie, from the love story of Danny and Sandy, which was more central in the film than it is on stage,’’ he says. “We also took some moments and songs from the stage play that weren’t in the film. We really wanted to . . . make our own ‘Grease’ that will honor and stand up to both of those and also be the first ‘Grease’ that many people will see.’’

Tveit, whose Broadway credits include “Hairspray’’ and “Wicked,’’ says he feels lucky to be working at a time when TV musicals are back in favor.

“It’s something an entire family can sit down and watch together,’’ he says. “I’m so grateful . . . the musical form isn’t looked down on like it was for a time.’’