British fashion designer Matthew Williamson‘s career highlight was Prince performing at his show.

The highly-regarded fashion designer says that the most rewarding moment of his working life was being asked by the eccentric pop star if he could sing during his renowned 2007 catwalk show, which received a standing ovation.

“Coming in at number one for me would be my 10th-anniversay show for Spring/Summer ‘08. Just 48 hours before kickoff, my PR received a phone call from Prince’s people, saying he wanted to perform at my show.”

As excited as he was, the 37-year-old designer admits that he was unprepared for the pop star’s unusual demands: “He wanted a stage to be built and we were told he needed a white room backstage. We had a black room, but, apparently, he wouldn’t go into that. So we literally staple-gunned white over black fabric. On the day, his manager called to say he was still in bed at London’s Dorchester hotel with an hour to go. Then, just when the show was about to happen, I saw Prince walking in. There was no rehearsal. He just went and sat in the front row. And when his track came on, up he got with his mike, and his girls came out and did their performance down the skinny little runway.”