Attending a Lakers game at LA’s Staples Center, “Entourage” star JEREMY PIVEN freaked when he realized he’d left his cell phone in his car. In a trademark diva move, Piven interrupted a guy behind him who was talking on his cell and asked: “Hey, let me borrow your phone when you’re through!” The stunned guy, who was on with his girlfriend, told her: “Hey, Jeremy Piven needs to use my phone. Gotta go.” He happily surrendered his cell, but Piven made one, two… three calls! The guy repeatedly tapped him on the shoulder, but the star kept holding up a finger in a “just one more minute” gesture. When Piven finally gave the phone back, he told the guy: “Sorry, but you’ll need to charge this. It’s dead. But, thanks.” Dumbfounded, the guy took a deep breath – then got over it all when Piven signed an autograph for his girlfriend.