Prince showed up to a screening of “Black Swan,” Darren Aronofsky‘s ballet-themed thriller, in Los Angeles the other night in typical rock-star fashion. “He showed up just as you would expect Prince to do — late, with dark sunglasses and high heels,” said a witness. The Purple One’s tardiness delayed the screening 20 minutes, but it seemed to be worth the wait. “He said he really liked the film as he walked out,” said our source.