Adrian Grenier's On-Set Birthday

Despite the fact that many celebrities go all out and throw massively excessive birthday parties, Adrian Grenier spent his 32nd birthday hard at work in Beverly Hills.

The “Devil Wears Prada” stud was busy on the set of his hit HBO gig “Entourage” all day in preparation for the show’s fifth season, slated to begin airing in September.

But not to worry, co-stars Kevin Dillon, Jerry Ferrera, and Kevin Connolly made the day a little more special with a beautiful birthday cake for their buddy.

Among the names on the celebrity-studded guest star list for Entourage’s season five are Gossip Girl’s Leighton Meester, Arrested Development’s Jeffrey Tambor, The Sopranos’ Jamie-Lynn Sigler, and rapper T.I..

Gossip Girls

Enjoy the pictures of Adrian Grenier celebrating his birthday on the set of "Entourage" (July 10).