Jimmy Fallon, Justin Timberlake delight US Open crowd

We've had a number of celebrity sightings at the 2015 US Open, but this moment featuring Jimmy Fallon and Justin Timberlake takes the cake.

While Roger Federer was breezing through his quarter final against Richard Gasquet, one of the major highlights occurred in the stands.

During a change of ends, Fallon and Timberlake gave their best Beyonce impersonation as 'Single Ladies' was played throughout the arena.

Given the one-way traffic that occured on-court (the lone match in the Arthur Ashe night session that ended in a 6-3, 6-3, 6-1 rout that took just 87 minutes) fans needed some sort of entertainment.

It comes on the back of a number of memorable fan moments so far at the US Open: