Stars team up for "Imagine" UNICEF fundraiser

Some of the biggest stars have teamed up to sing John Lennon's "Imagine" to help turn the song into the world's biggest sing-along.

Courtney Cox, David Arquette, Scott Foley, Rumer Willis and Katy Perry are just a few blasting their pipes to the new song for UNICEF.

Some old recordings of Lennon are also included in the video. You can take part by recording your own version of the song and sharing it with the hashtag Imagine. If yours is chosen, it could be part of the final track that will debut on January 1.