Clooney calls police over Larson threats

George Clooney has instigated a police investigation after a mysterious caller reportedly warned him to break up with his girlfriend Sarah Larson.

The star received a voicemail from an unknown number urging him to end his relationship with Larson. A calm male voice is heard to say: "Dude, your friends asked me to give you a message: Dump the b**ch before you're sorry!"