Lady Gaga performed an hour-long jazz set Thursday, at the American Foundation for AIDS Research's tribute to Ryan Murphy.
"I love Ryan so much, and I'm so, so happy to be here," said Gaga, who stars on the current season of the writer-director's FX hit, "American Horror Story."
"He's really my friend and he's a wonderful person," she said.
Murphy said the evening raised $3.1 million toward that goal.
Gaga contributed to the total during a live auction conducted by Sharon Stone. Gaga bid a winning $200,000 on a photograph of Elizabeth Taylor flipping the bird. Cuba Gooding, Jr. engaged in a brief bidding war with billionaire Barry Diller for a pair of platinum diamond earrings. Diller won with $60,000.
Gwyneth Paltrow hosted the fundraiser at Milk Studios, which also included appearances by Julia Roberts, Angela Bassett, Matt Bomer and Cheyenne Jackson.
Murphy may have been the guest of honor, but Gaga was the reigning diva. She wore a long dusty pink gown with floor-sweeping kimono sleeves, an intricate diamond collar, and a platinum blonde beehive.
"You know, there are a lot of gentlemen here, but nobody's offered me a glass of Champagne yet," she said from the stage.
Gaga performed "Bang Bang (My Baby Shot Me Down)," which she recorded for her 2014 album with Tony Bennett, "Cheek to Cheek."
She played piano as she sang her new single, "Til it Happens to You," a song she co-wrote with Diane Warren for the 2015 documentary "The Hunting Ground." Gaga said her performance was inspired by Murphy.
For her closing number, Gaga ditched her dress for a tuxedo jacket and not much else. She sang "La Vie en Rose" – in French, bien sûr.