The "24K Magic" hitmaker was all praise for the Oscar-winning singer, with whom he recorded song "All I Ask," reported ET online.
"She's incredible. There was a moment when she was singing in the booth, and I'm not exaggerating at all and the water was vibrating. Like you know that scene in Jurassic Park. She's got some pipes on her, and she's just a superstar.
"She walks into the studio, she's got all this attitude, she's a diva, she's like, 'I don't want to do this. I don't like that'. And then as soon as we hit a couple chords that she liked, we started rolling, and that's where we got that song from," Mars said.
"I don't know what she's waiting on, man.