The cheek of it! Tour de France rider slaps mooning fan on backside (VIDEO)

A cheeky salute from cycling fans was too much to bare - sorry, bear - for one Tour de France rider as he spanked a mooning supporter on the backside during stage nine of one of sport’s biggest events.

A viral video on Twitter shows a group of male fans with lowered shorts and jeans as the peloton made its way past on Sunday’s route from Saint-Etienne to Brioude.    

The bare-faced greeting was met with a slap from a cyclist decked in the red and dark blue of the Bahrain-Merida team.

The footage shared on social media has gone viral, racking up more than 30,000 likes.

A follow-up picture also showed the red mark made by the rider’s palm-slap.

Fans along the Tour de France routes get famously close to the competitors, sometimes causing crashes.

Last year, former champion Vincenzo Nibali was forced out after fracturing his back in an incident reportedly involving an overzealous supporter.

Fans down the years have also shown their displeasure at certain riders, with some infamously throwing urine at then-Team Sky rider Chris Froome in 2014 as they accused him of being a “doper.”

Monday’s stage 10 takes the riders along a 218km (135 mile) route from Saint-Flour to Albi. Frenchman Julian Alaphilippe is in the yellow jersey, while defending champion Geraint Thomas of the UK is back in fifth.