TV

Allison Williams flying high in ‘Peter Pan Live!’ rehearsals

She didn’t have to audition.

It’s unheard of that a TV actress who had never done a live Broadway musical was given the lead in “Peter Pan Live!,” NBC’s production of the Mary Martin musical airing Dec. 4.

But Allison Williams has that kind of luck.

“I must send off that much of an overachiever vibe,” Williams says in a West Side rehearsal space.

The actress, known primarily to “Girls” fans as the gorgeous-but-uptight Marnie Michaels, hounded her agent for the role once the project was announced.

“It wasn’t uncute and desperate,” she says of her campaign. “It was very enthusiastic.”

Once cast, Williams, 26, headed out to the show’s Long Island sound stage to step into a harness and learn how to fly.

“The hardest thing is to face direction,” she says. “You’re on an axis, you’re spinning around in circles. They determine how high you go, side-to-side. It’s up to you to face a certain direction. Which is incredibly difficult and requires a lot of practice.”

Williams stands in her rehearsal tights and brown Peter Pan demi-boots and demonstrates how the requisite swordplay helped her shift her center of gravity to be more masculine.

The exquisite diamond engagement ring on her hand has been a distraction, though. (Her fiancee is Ricky Van Veen.) “It is funny when I’m being Peter Pan and I look down, it’s like, ‘Oh yeah, I have jewelry on.’ I haven’t taken it off,” she says. “That’ll be the last phase.”

Even though she has never performed in live musical theater, Williams says she is not petrified.

“I’m not scared because everyone is working to the best of their ability. I am really type A in this preparation,” she says. “And the other thing is that my biggest training ground is improv. I’ll know how to handle things if something goes wrong. The myriad things that can go wrong is why most of America will tune in.”

Twenty-two million people tuned in last December for NBC’s live production of “The Sound of Music” to see if star Carrie Underwood could pull off the role Julie Andrews immortalized. The reviews, to be kind, were scathing.

Co-executive producer Neil Meron, who also cast Underwood, is justifiably proud of the numbers and takes the criticism in stride.

“The idea of these live events, they’re like sporting events,” he says. “For whatever sport, or blood sport, the audience got out of it, the show was an entertainment and we wanted first and foremost for it to be an entertainment. And we’re very proud of it, by the way.”

To bolster Williams’ performance (and morale), the producers have surrounded her with a top-notch cast. Christopher Walken plays Captain Hook; Tony winners Kelli O’Hara and Christian Borle play Mr. and Mrs. Darling (Borle doubles as the pirate Smee).

“She’s wonderful. She’s beautiful. She’s very believable as Peter,” Walken says. “And she has a beautiful voice.”

Meron thinks throwing his untried star in at the deep end of the pool among these pros is worth the risk.

“We love the fact that she’s new. We love the fact that she’s on the rise, no pun intended,” he says. “And to have her in combination with the coolest of the cool, Mr. Christopher Walken, seems like the right DNA for this project.”