Justin Bieber didn't tell bosses at the Grammy Awards he planned to perform in his underpants

Bieber's fashion choice also surprised organisers because the singer didn't tell anyone about his plan. During an appearance on the Rolling Stone Music Now podcast, Grammy Awards ex ecutive producer Ben Winston said: "I don't think he decided what the outfit would be until he walked on stage.

"He's not even really going: 'This is what I'm going to do'. When we had got reached out to him about his creative, he was just like, I'm just going to get on stage and sing."

Winston went on to reveal the Baby star didn't need much rehearsal time for the performance - only taking 15 minutes out of his allotted 90 minutes.

He explained: "It was brilliant. We are seven minutes into his hour-and-a-half rehearsal. And he goes: 'How'd it look to you? You happy with it?'

"And I was like: 'Oh, my God. It looked beautiful. I loved it'. And he went: 'Okay, fantastic. See you Sunday!'"

However, Winston did ask the singer to perform the song one more time so the camera operators could set up their shots.

He added of Bieber's performance: "It was what he wanted to do. It was all him. It was a career-defining moment for him. It was so different to what we've seen over the years."

The awards show also featured a major flub by pop superstar Cher, who mistakenly announced Luther Vandross as the winner of Record of the Year even though the singer-songwriter passed away in 2005.

The Believe hitmaker swiftly corrected herself and awarded the gong to the real winner - Kendrick Lamar, who won Record of the Year for his SZA collaboration Luther.

During his appearance on the podcast, Winston insisted Cher was fully briefed before going on stage, but he wouldn't want to erase the moment from Grammys history if he was given the chance.

He explained: "I promise you, we had briefed her, and I promise you, what she had to do was in the prompter.

"If I could go back in time, I'd want that to happen again."

Winston also insisted Cher was "happy" with her on-stage presenting, despite the initial error. He added: "She's happy with it. She had a great time. "You want a bit of anarchy."