Watch Cristiano Ronaldo sing a Rihanna song in trailer for new documentary

Here's Cristiano Ronaldo as you've never seen him before.

The Real Madrid star is filmed singing the Rihanna hit 'Stay' for his Portugal team-mates as they travel to a game on an aeroplane.

Never one to give a half-hearted performance, Ronaldo throws himself into the song, with no end of exaggerated hand gestures and intense facial expressions.

Early on in the song he says "this part's cool" as he gets into his stride.

And after a rousing rendition of the hit he receives a standing ovation from team-mates. An ovation led by the ever modest Ronaldo, who seems as impressed with his singing as he is by his football .

The video footage forms part of a trailer for the new documentary titled Ronaldo.