Justin Timberlake showed off his funny side again last night, introducing Madonna at the Rock and Roll Hall of Fame induction ceremony:

Justin has revealed that one of the best days of his life was when Madonna told him to drop his trousers.

“We had a recording session in London, and I wasn’t feeling well. She said: ‘Would you like a B12 shot?’ She reached into her handbag, pulls out a ziplock bag of B12 syringes and says: ‘Drop ‘em.’ I don’t know what you say to that, so I dropped my pants. She gave me the shot in my ass. It was one of the greatest days of my life.”