Pharrell Williams is one of the stars involved. Christopher Polk/Getty A group representing some of the biggest musicians in the world is preparing for a legal fight with Google because it says that YouTube doesn't have the rights to about 20,000 tracks.

Time reports that a legal group called Global Music Rights is demanding YouTube take down thousands of songs because it doesn't have permission to share their music.

The newly formed group is representing music industry heavyweights like Pharrell Williams, the Eagles, John Lennon, Chris Cornell, and Smokey Robinson among others.

Google isn't giving in to the musicians' demands, though. It is insisting that it does have the correct rights, and is refusing to remove the contested music. Now, the musicians say that if YouTube doesn't remove their music, they will hit back with a $1 billion lawsuit.

The Hollywood Reporter asked Irving Azoff, the legendary manager who is representing the musicians against Google, why he's singling out the tech company over other streaming sites. "Because they are the ones that have been least cooperative," he said. "[It's] the company our clients feel are the worst offenders."