Leave it to Jimmy Fallon and Justin Timberlake to bring some laughs to the US Open. The BFFs broke out into a full-on dance routine to Beyoncé's "Single Ladies" while taking in Roger Federer's match during the tournament on Wednesday. As the song played, Justin and Jimmy did their best Queen Bey impressions, even showing off some of the same choreography from the music video — if you recall, Justin starred in a sketch with Beyoncé as one of her "Single Ladies" backup dancers during his SNL hosting gig in 2009. We got to see even more of Justin and Jimmy's hilarious antics on Wednesday night when the singer made his triumphant return to The Tonight Show and performed the sixth installment of History of Rap. Keep reading for video and photos of the pair's US Open fun.