Guy Sebastian has surprised Ben Fordham by singing ‘Happy Birthday’ to him live in-studio.

The famous Aussie singer has recently taken home ARIA Awards for best video and song of the year for his hit single Choir.

Click PLAY below to hear him sing ‘Happy Birthday’

Mr Sebastian tells Ben the song reached heights he hadn’t expected.

“I’ve never, ever, had as many messages about any song I’ve ever released as I’ve had about Choir.

“I didn’t wanna write something that is a sad mellow reflection of someone’s life. I wanted to celebrate it.”