President Bill Clinton rang in his 65th birthday on Saturday night at the Hollywood Bowl with a star-studded charity fundraiser called "A Decade of Difference," celebrating the tenth anniversary of the Clinton Foundation. Arguably making more waves than even the Clintons was the performance by Lady Gaga, who was channeling the iconic Marilyn Monroe's "Happy Birthday" song to John F. Kennedy when she announced that she was "caught in a Bill romance."

"Well I'm having my first real Marilyn moment," Gaga said, showing up on the stage of the packed event with platinum blonde hair. "I always wanted to have one, and I was hoping that it didn't involve an accident with some pills and a strand of pearls. So here we are."

Bill, Hillary, and Chelsea Clinton were all in attendance and looked delighted as Gaga kicked off her "Bad Romance" tune. Later Clinton acknowledged the performance with a little joke. "I am the only person in history who got to be President and then had a post-presidential birthday party attended by both Lady Gaga and the Secretary of State," he said, referring to Hillary. "I want to thank Hillary because we met 40 years ago this year. When I met her, she was already doing the kind of work you see here long before it was cool."

The evening also held performances by U2, Stevie Wonder, and Usher, who split his pants during his spirited cover of The Beatles' "With a Little Help from my Friends," according to MTV. Other celebs in attendance included Ashton Kutcher, Ellen DeGeneres, Jason Segel, Chevy Chase and Colin Farrell.

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