Even with a galaxy of big stars on hand to honor former President Bill Clinton on his 65th birthday, it was, of course, Lady Gaga who made the big headlines Saturday night at the four-hour Clinton charity fundraiser, "A Decade of Difference."

Emerging on the stage from an all-white tree house, Gaga sang a sedate, unplugged version of "Born This Way" on keyboards, while wearing a giant cloth hat and flesh-colored cape over a similarly colored top and leggings. The backing track soon pumped up and a group of dancers came out as Gaga made her way down to the main stage and sang the line, "Don't be a drag, just be a queen," while the former president and his wife, Secretary of State Hillary Clinton, clapped and smiled along.

Wearing a blond wig, Gaga paid homage to Marilyn Monroe by changing some of the lyrics to "Bad Romance" to "Bill romance," prompting the president to later declare, "I thought, 'My God, I get Lady Gaga, and I will have a heart attack celebrating my 65th birthday.' "

"Well, I'm having my first real Marilyn moment," Gaga joked after the opening, running her fingers through her mane. "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."

Gaga's set also included a run through "Edge of Glory," during which she said, "I wish you were playing sax with me tonight, baby," an homage to late E Street horn man Clarence Clemons, who played on the song, but a quip that Clinton could have also taken as a nod to himself, as he's also known for blowing a mean sax.

The show took place at the Hollywood Bowl to celebrate the 10th anniversary of the Clinton Foundation and, though his birthday was on August 19, Clinton was still feeling very thankful for all the fuss.

"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," Clinton said to the crowd, which included such stars as Colin Farrell and Chevy Chase. "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."

Also on hand to fete the former president was Stevie Wonder, who performed "Superstition," "Sir Duke" and "For Once in My Life," and U2's Bono and the Edge (accompanied by a laptop), who did acoustic versions of "Desire," "I Still Haven't Found What I'm Looking For," "Sunday Bloody Sunday," "One," "Staring at the Sun" and "Miss Sarajevo." The pair also unveiled the first-ever live version of "A Man and a Woman" from 2004's How to Dismantle an Atomic Bomb, dedicating it to Chelsea Clinton and her husband, Marc Mezvinsky.

The U2 singer praised the former president for his work in helping to broker peace in Ireland, saying that "at the top of the list" for playing the gig was the fact that his homeland is "truly at peace, north and south, because of the 42nd President of the United States of America," whom he dubbed the "most beloved president since JFK for us Irish."

Usher made news because he danced so hard that he split his pants during a mini-set that included a cover of the Joe Cocker take on the Beatles' "With a Little Help From My Friends," as well as his own "Yeah!" and "OMG." Also performing were Colombian pop star Juanes, country singer Kenny Chesney, Grace Potter and K'Naan. Among the celebrities on hand to make introductions were Ashton Kutcher, Ellen DeGeneres, Jason Segel and Maria Bello.