Watch: Prince William and Kate Middleton uncomfortable with Brad Pitt's Megxit joke at BAFTAs

Brad Pitt has spent this year's awards season picking up trophies and using his acceptance speeches to drop some spicy one-liners - and he's continued the tradition with his latest win. 

The Once Upon A Time In Hollywood star won Best Supporting Actor at the BAFTAs, this time adding to his usual gags about his love life with a jibe at Prince Harry and Meghan Markle. 

Pitt's co-star Margot Robbie was tasked with delivering the zinger, making a speech on the actor's behalf as he wasn't able to attend. 

"He says he's going to name this Harry," Robbie said, holding Pitt's trophy aloft. 

"Because he is really excited about bringing it back to the States with him." 

Cameras immediately cut to Prince William and Kate Middleton, who were in the audience. The Duke and Duchess of Cambridge both reluctantly applauded, and while Kate appeared to laugh along, William's smile looked somewhat more strained. 

"His words, not mine!" Robbie said before quickly exiting the stage. 

The joke made waves on Twitter, where fans thoroughly enjoyed the unexpected moment. 

"Brad Pitt's speech about the US taking Prince Harry then the camera cutting to William's face of thunder is my highlight of the BAFTAs," one tweet read. 

"Brad Pitt/Margot Robbie making a Harry and Meghan joke in front of Will and Kate is a big yikes," said another. 

One Twitter user suggested Pitt should start a career in stand-up comedy. 

"[He's] funnier than 99 percent of funny people out there. He's ripped up award-season." 

Pitt's speech at the prestigious British awards ceremony opened with a one-two punch about Brexit and his own relationship status. 

"Hey Britain! Heard you just became single. Welcome to the club!" Robbie read for Pitt. 

"Wishing you the best with the divorce settlement."

Pitt's BAFTA is his third Best Supporting Actor win of the year, having already picked up the honour at the Golden Globes and the Screen Actor's Guild awards.