NBC has found its Peter Pan: Allison Williams.

The Girls actress will star in the title role of the live Sound of Music follow-up, which NBC will broadcast on Dec. 4, NBC announced Wednesday morning.

She joins Christopher Walken, who was previously cast as Captain Hook.

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“We couldn’t be happier that Allison Williams is our Peter Pan,” said Robert Greenblatt, chairman at NBC Entertainment. “She’s a lovely rising star on the award-winning show Girls — where she occasionally shows off her incredible vocal talent — and we think she will bring the perfect blend of ‘boyish’ vulnerability and bravado to save the day against Christopher Walken’s powerful Captain Hook.”

"Allison Williams is a major find," said executive producers Craig Zadan and Neil Meron. "She will reinvent the iconic role of Peter Pan with her wit, her warmth, her dynamic flying and her wonderful musical abilities. The score will be sung beautifully and introduced to a whole new generation of families."

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Since graduating from Yale University in 2010, Williams — who reunites with her father, NBC Nightly News anchor Brian Williams, on the same network — has starred as Marnie Michaels on the Emmy-nominated Girls, where she's exercised her musical pipes. She recorded several songs for the Girls soundtrack and filmed online videos that have garnered millions of views. Williams also appeared on The Mindy Project and The League.

“I have wanted to play Peter Pan since I was about three years old, so this is a dream come true,” said Williams. "It’s such an honor to be a part of this adventure, and I’m very excited to get to work with this extraordinarily talented team. And besides,” added Williams, "what could go wrong in a live televised production with simultaneous flying, sword fighting and singing?"

The news comes months after NBC named Peter Pan as its next live production, following a successful go at bringing The Sound of Music to the small screen with an impressive 18.6 million viewers tuning in to its premiere telecast last December.

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Sound of Music producers and Broadway veterans Zadan and Meron, who also executive produced NBC's Broadway drama Smash, are back at the helm.

During the winter Television Critics Association press tour on Jan. 19, Greenblatt told The Hollywood Reporter that there likely wouldn't be a role for Sound of Music star Carrie Underwood, whose performance was largely panned by critics. At the time, Greenblatt hinted that the central role of Peter — traditionally played by a woman — would likely go to a male actor.

In a chat with THR in December, Greenblatt was hopeful that they would be able to produce the next live production more "more efficiently" than Sound of Music, which took 18 months to produce.

Based on James M. Barrie's revered book and musical, NBC's new take on Peter Pan comes after the network in 1955 staged a live broadcast of the Broadway production of Peter Pan that opened in 1954. The show, starring Tony winners Mary Martin and Cyril Richard, drew 65 million viewers — the highest rating for a single-night program at the time. NBC later broadcast the show live again in 1956 and 1960. It was also the first broadcast of a musical in color.

Pan, a big-screen Peter Pan feature from Pride & Prejudice director Joe Wright, is also in the works, with Hugh Jackman and Garrett Hedlund starring.

Fox is also getting into the live musical game, slotting a three-hour production of Grease starring a young ensemble cast for broadcast in 2015. NBC will be producing a live version of The Music Man, likely following Peter Pan in 2015.

Williams is repped by CAA.

Lesley Goldberg contributed to this report.