Michael Buble performed touching duet with son Noah before his cancer diagnosis

Video of Michael Buble and his young son singing together on stage has surfaced online, a month after his son's liver cancer diagnosis.
In the clip, the sweet bond between the singer and his eldest song is clearly seen.
"Ladies and gentleman, I promised I'd get someone out to do a bit of a duet with me. I promised him, I said. 'dude if you have your nap I'll let you sing'." says Michael.
Fans in the crowd guessed what he was getting at and starting shouting, "Noah, Noah, Noah".
The two then sang an a cappella snippet of Michael's song Nobody But Me.
The singer's three-year-old son is currently undergoing chemo treatment in America while his parents take a break from their careers.
Noah has a 90% chance of beating cancer, and Michael and his wife Luisana have started doing home renovations to help with Noah's recovery.