AceShowbiz -

On Valentine's Day, actor Vin Diesel posted on his Facebook page a video of himself singing in a karaoke, covering Rihanna's "Stay". The song is RiRi's latest single which she performed last Sunday at the 55th Grammy Awards and whose stripped-down music video she just released a few days ago.

Standing beside a projection of the "Stay" music video, Diesel sang along to Rihanna's emotionally-stirring track, and moved between his distinctly deep, low voice and a few not-so successful attempts on some high notes. He wrapped up his rendition with a big smack after three successive "Happy V-day" greetings towards the end.

The sentimental performance instantaneously went viral after it was posted online, since it was quite uncharacteristic for the tough action hero to bare his romantic side to his fans, much less sing such a sensitive song. The famous movie star really surprised the 38 million fans who "like" him on Facebook with his less-than-perfect but very endearing version of the new hit.

Diesel starred in the hit films "Saving Private Ryan" and "Pitch Black" before rising to prominence with "Fast and Furious", following it up with the rest of the "Fast" movie series. He is set to star in the film's sixth installment as well as the fourth "Riddick" flick, both slated for a 2013 release.