AceShowbiz -

How Allison Williams will look like as the boy that never grows up, Peter Pan, in NBC's live musical production has been revealed. On Wednesday, September 3, the network released the first official photo of the "Girls" star in costume as the titular character.

The 26-year-old actress also shared the picture on her Instagram, captioning it, "The transformation begins! My first shoot as Pan." She rocks a short do in the image, but it's just a wig. She revealed, "Fun fact: I was all ready to cut my hair, then was told by the folks who actually know what they're doing that a wig works better for everybody."

Appearing on "Today" to talk about her role in the upcoming holiday special, she said, "It's an absolute dream come true; the whole process just as it (is) sort of starting to get going is so fun; already I can only imagine what the next couple of weeks and months are going to bring."

Williams, who is the daughter of NBC News anchor Brian Williams, gushed about the combination of live TV and theatrical format. "We're so excited about the live part of it," she said. "I think that's what makes it so fun. That's what makes it exciting that it's theater, but it's right in the comfort of your own home. That's what attracted me to it."

"Peter Pan Live" will premiere December 4 on NBC. Christopher Walken is cast as Captain Hook, while "Smash" alum Christian Borle plays two roles, Captain Hook's right-hand man Smee and the Darling kids' father, Mr. Darling.