The actress, 41, made a surprise cameo on stage Monday night as part of the 24 Hour Plays on Broadway charity event in New York. Surprising the audience and her castmates, she played the spirit of a dead dog in The Bitch Downstairs, one of six short plays written and performed in the space of 24 hours.
"She's known about the show for weeks, but whether or not she could perform depended on her shooting schedule. She actually came right from the set," a source said of Aniston, who has been filming the comedy Wanderlust.
Aniston shared the stage with Kyra Sedgwick, Sam Rockwell, Lee Pace and Nia Vardalos, among others, at the event, which was sponsored by Montblanc and benefiting the Urban Arts Partnership.
Dressed casually in jeans, a furry vest, a white tank and heels, Aniston mingled with friends at the afterparty at B.B. King Blues Club & Grill in Times Square. She chatted with actresses Elizabeth Banks and Leslie Bibb and hit the dance floor for a few songs before leaving around 1 a.m.
Aniston's good friend Kathy Najimy also performed in the plays but she stayed mum on whether or not she knew about Aniston's big surprise.
"I can't say! I can't say," she said with a smile. "She did fantastic, and the crowd went wild. What's not to love? It's Jennifer Aniston."