Jennifer Aniston Sings "Yellow Submarine" as Demi and Ashton Look On

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Do we smell a Grammy? Jennifer Aniston sings!

The 40-year-old actress made a surprise appearance at Monday's 24 Hour Plays event in New York City -- and took to the stage to offer a rendition of The Beatles' "Yellow Submarine" for the crowd, which included Demi Moore, Ashton Kutcher, Naomi Watts, Brooke Shields and Rosie Perez.

See photos of all the celebs at the 24 Hour Plays event at PopSugar.com!

Aniston and her 24-Hour Play mates worked together to write, direct and perform six 10-minute plays in less than one day. Added pressure for Aniston? She didn't get to see her script until 12 hours before the show started! Proceeds from the sold-out charity event benefited Urban Arts Partnership, which raises money for school arts programs.

Revisit Aniston's red carpet looks over the years.

The actress celebrated her accomplishment after the final curtain call with Kutcher and Moore at an after-party at New York City's Crest Lounge's Opera Ballroom.

The 24-Hour Plays also served as a primer for Aniston's upcoming role in The Goree Girls, where she'll sing and play the dobro guitar.

Check out the day's top celeb news photos.

The drama -- a departure for Aniston, who normally stars in romantic comedies -- is based on a true-life story about a group of women imprisoned in Texas who start a country and western band. Director Michael Sucsy says he'll cast real-life musicians alongside the actress.

Aniston -- who is also producing the movie (out next year) -- last sang while guest starring on 30 Rock, where she serenaded Alec Baldwin for his birthday.

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