Chart-topping singer James Blunt has fallen in love with karaoke after treating some revellers in Sydney to an impromptu gig.

The former Army captain was in a sing-a-long bar in Sydney with some mates when he heard a gaggle of girls belting out one of his tunes.

Having had a tipple he decided to step in and help them.

James said: “It was one of those places where you get a small room to yourselves and happily sing away in the privacy of your own group.

“We did it for an hour then we heard three English girls singing Goodbye My Lover from the next room.

“I burst in, grabbed a microphone, sang them the last chorus, said ‘Thank you and goodnight!’ and left. All we heard for the next 20 minutes was them screaming.”

The singer and songwriter had such a good time he hopes he can repeat the experience very soon.

He said: “I’m going to start hanging around karaoke bars more often.”