Sean Penn’s charity benefit for Haiti ended with a surprise on Saturday night: a reunion performance by U2. The rock group took the stage for their first performance together in four years to play a three-song set to the star-studded crowd of 300 at the Beverly Hills’ Montage Hotel.

“It’s been a while since we played a hotel lounge,” singer Bono told the crowd when the rock group took the stage, according to the Hollywood Reporter. “I think the last time was a Bar Mitzvah.”

There to take in the U2 performance was a crowd of big-name stars including Julia Roberts, Kathryn Bigelow, Steve McQueen, Uma Thurman, Idris Elba, Michael Douglas, Charlize Theron, Emma Thompson and Gwyneth Paltrow. The annual charity event, now in its third year, was established by Penn to raise money for Haiti relief. All of the proceeds from the gala—which included an auction of artwork by Banksy and Jeff Koons—is donated to the J/P Haitian Relief Organization. This year, Penn’s event raised $6 million for the charity.

[Hollywood Reporter]