The video, which shows the two stars singing 'Driven to Tears', was originally taken during Sting's 60th birthday concert in October 2011.
Robert Downey Jr. sure can sing, but he is actually a very good singer. In a video that arrived via YouTube, the "Iron Man 3" star is seen joining Sting onstage to deliver an amazing live performance of a song called "Driven to Tears".
Backed by a band, Downey showed off his vocal while Sting sang and played his guitar. The 48-year-old actor, wearing a black suit, looked relieved and satisfied when he finished the song. He even received a standing ovation from the crowd.
The performance was a part of Sting's 60th birthday concert which took place at Manhattan's Beacon Theatre in October 2011. The video, however, didn't surface online until recently. Since being uploaded on the biggest video-sharing site, it has so far garnered 1 million views.
Downey wasn't the only star at Sting's birthday concert at that time. Lady GaGa, Bruce Springsteen and Stevie Wonder were also featured as performers.
The duet between Downey and Sting also marked their second time to perform together. They previously collaborated to sing "Every Breath You Take" during a 2001 episode of "Ally McBeal".