Cast member T. Oliver Reid, who played one of Captain Hook's pirates, posted the video on social media, which has been shared hundreds of times since its publication.
Watch as Williams, still in costume, enters to cheers from her fellow cast members and gets a big hug from Tony Award nominee Kelli O'Hara, who played Mrs. Darling.
Read critics' reviews of Peter Pan Live! here.
Read Playbill.com's live chat from the night, recapping the best tweets, insider scoop, reader polls and more.
PHOTO EXCLUSIVE: Ryan Steele Takes Us to Neverland! A Day With the Lost Boys, Pirates, Peter, Smee and Wendy on the Peter Pan Live! Rehearsal Stage