Not the face!

David Beckham is clearly taking his cameo in director Guy Ritchie's upcoming King Arthur: Legend of the Sword seriously, undergoing some dramatic makeup work. The handsome 41-year-old athlete shared a preview of his look on Instagram on Tuesday, showing off his rotting teeth and scarred face.

"Rough day at the office @kingarthurmovie @guyritchie," he joked.

WATCH: EXCLUSIVE -- Charlie Hunnam Bummed He Never Got His Promised 'King Arthur' Sword, Cops to Stealing a Bike From 'Sons of Anarchy'

Beckham will make a cameo as a disgruntled knight in Ritchie's film, which stars Charlie Hunnam as King Arthur. Beckham previously worked with Ritchie in 2013 for his H&M commercial.

King Arthur: Legend of the Sword hits theaters on May 17.

WATCH: Shirtless Charlie Hunnam Heats Up the 'King Arthur: Legend of the Sword' Trailer

Watch the trailer for the highly anticipated movie -- featuring a shirtless Hunnam -- below.

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