Never mind his royal duties, Prince William is the king of karaoke, says Taylor Swift

American pop star Taylor Swift says Prince William has star quality, and that if he ever wants to sing with her again she'll be there.

The Duke of Cambridge famously shared a microphone with country singer Swift, 24, as the pair joined Jon Bon Jovi on stage for a rendition of Livin' On A Prayer at a charity function last year. Footage of the unlikely collaboration at Kensington Palace went viral afterwards.

Swift, who has enjoyed UK chart success with We Are Never Getting Back Together, said the royal possessed surprising vocal qualities.

She told the Mail on Sunday's Event magazine: "Both of us were more screaming than singing.

"But even through all that I could hear his voice and it is pretty good. A nice tone.

"I'd definitely say he's got star quality, and if he ever wants me to sing with him again, I'll be there."

The Stateside singer, previously romantically linked with One Direction's Harry Styles, described how William was initially reluctant to join the veteran rocker on stage.

She said the frontman jokingly enlisted the audience to "put pressure" on the royal to sing.

Swift, who is in England to play several dates at London's O2 Arena, said: "Prince William looked at me and said, 'I'll do it if you do it too', and then he took my hand.

"I was surprised and flattered and it felt surreal and completely natural at the same time.

"We jumped on the stage and started to sing and then we were really yelling.

"I still can't believe I've sung with Prince William."