The stars were together for nearly four years before splitting in 2007.

And backstage at the charity event it seems any bad feeling had been forgotten- Cam and JT were seen smiling and casually chatting to each other.

Justin performed Hallelujah at Hope For Haiti Now and told MTV News in the US it was the ideal track.

He explained: “Obviously, I was going to help answer phones and help make donations. But as soon as I got that call, all of a sudden ... it was kind of like a big highlighted neon-green [light], everywhere I looked: 'Hallelujah, hallelujah.'”