Prince‘s dressing room was restricted, even if you were The Boss or Madge.

Bobby Z, the drummer in Prince and the Revolution, spoke to The Guardian about the musician who died nearly 10 years ago on April 21, 2016, reflecting on their friendship. Among the anecdotes, the musician recalled Prince banning Bruce Springsteen and Madonna from his dressing room.

“Once there was a hilarious moment when Bruce Springsteen and Madonna came backstage but Prince’s dressing room was off limits to them, so they had to use the band’s toilet,” Bobby Z remembered.

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The drummer, who was friends with Prince for over 40 years, also said that he “found meeting other celebrities very uncomfortable unless he was a fan,” and would get “bashful or embarrassed,” despite being a major star himself. “There could be huge stars and he just wouldn’t give them the time of day. So besides shaking Elizabeth Taylor‘s hand I don’t know if he’d be interested in chatting,” he added.

However, “When he met David Bowie at Paisley Park [Prince’s longtime home and studio] it was a warm moment, because he felt that they were equals.”

The Grammy winner was found dead at Paisley Park, outside Minneapolis. His cause of death was ruled as an accidental overdose caused by “fentanyl toxicity” and that “the decedent self-administered fentanyl.” He was 57. Many mourned his passing throughout Minneapolis, the U.S. and the world, lighting up buildings and structures with purple displays.

Days after his death, The Boss honored Prince with a cover of “Purple Rain” to open his Barclays Center concert in Brooklyn, per Vanity Fair. Covered in purple light, Springsteen gave his best rendition of the 1984 track. “Prince forever,” Springsteen said. “God bless.”

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Madonna paid tribute with an Instagram post of her and Prince, who cowrote “Love Song” for her 1989 album Like a Prayer. “He changed the world! A true visionary! What a loss. I’m devastated. This is not a love song,” she wrote, per Mashable.

Madge also honored Prince with a performance at the Billboard Music Awards in May 2016, singing “Nothing Compares 2 U,” which he composed and wrote but was made famous by the late Sinéad O’Connor‘s rendition.

Bobby Z, whose real name is Robert B. Rivkin, looked back fondly on his years with prince with Prince. “Playing with Prince was like being in the purple marines: he might toughen you up or break you down, but he’d bring you to a place you didn’t think you had,” he concluded to The Guardian. “For a moment you might even turn into a superhuman like him.”