WATCH: Justin Timberlake and Jimmy Fallon dance to <em>Single Ladies</em> at the US Open

Cape Town – Justin Timberlake and Jimmy Fallon proved they can just about do whatever they want wherever they want!

The comedic duo were at the US Open to enjoy a quarterfinal match between Roger Federer and Richard Gasquet (Roger Federer won ICYMI) but before things got serious on the court, things got silly in the crowd.

Beyoncé’s Single Ladies came on and of course Justin and Jimmy just couldn’t let their feet behave.

Because who can sit still when Queen B is calling for all the single ladies?!

Watch them put their hands in the air like they just don't care...

Of course Justin has had some practice.

We all remember when he dressed in a tight black number and did the dance with Queen B herself on SNL.

Here it is again just to make you smile...