Usher was left stunned last week (ends16Oct15) when President Barack Obama marked the R&B star's birthday with a White House sing-along.

The Yeah! hitmaker was taking part in a meet-and-greet in the Oval Office when a White House staff member presented a candlelit cupcake to Obama, prompting the leader to break into song.

The newlywed 37 year old shared a video of the sing-along on his Facebook page on Saturday (17Oct15), adding the caption, "So this really happened the other night…The President and First Lady sang me Happy Birthday at The White House & I got to perform for them. I couldn’t be more grateful for this moment and all of the birthday wishes from everyone. THANK YOU!!!!!"