Watch Paul Allen And Adrian Grenier Rock Out On A Massive Yacht In Cannes

Microsoft cofounder Paul Allen threw an exclusive party on his enormous "Octopus" yacht yesterday. The annual event is one of the hottest tickets at the annual film festival in Cannes, France, drawing a long list of celebrities and socialites.

One highlight of the party was Allen's performance with "Entourage" star Adrian Grenier. Allen plays in a band called "The Underthinkers," who released an album called "Everywhere at Once" last year. It features guest performances from members of classic rock bands Heart and the Eagles, and Allen wrote or co-wrote each song.

Watch him rock out on the guitar, with Grenier on the harmonica.