"Entourage" star Jeremy Piven attended one of the most talked-about parties in NYC this week -- without even meaning to!
"I'm really embarrassed -- I didn't know it was Britney's birthday party! I think I was the one guy who didn't know!" Piven tells Us Weekly, adding, "I did not speak to the birthday girl," Jeremy adds, "I fortunately have nothing to report."
Piven hit up Tenjune -- where Brit's NYC bash was held -- after his Broadway performance in "Speed the Plow," and partied with the club's owners Eugene Remm and Mark Birnbaum.