Cape Town - It seems that Springbok scrumhalf Faf de Klerk is not the only one ready to pose in his patriotic South African underpants.

Bok captain, Siya Kolisi has added his support to the "#FafChallenge" which according to News24 is an undertaking to get men to check their "crown jewels" for signs of testicular cancer.

Kolisi took to Instagram to post a pic of himself supporting the campaign after he, and a host of other Springboks were challenged to do so by De Klerk. 

"Challenge ACCEPTED! Testicular cancer is one of the most common cancers in young men. Early detection = high cure rate," said Kolisi in a post in which he went on to then challenge Springbok winger, Cheslin Kolbe as well as No 8, Duane Vermuelen to do the same.

Kolbe was quick to answer his captain's call saying "I see you called me out, so here I am! What’s more awesome than scoring the final try in the Rugby World Cup? Ensuring that you’re healthy. So, be ballsy enough to check your balls. If caught early, testicular cancer can be beaten."

Other Springboks to take up the challenge include Makazole Mapimpi and Jesse Kriel.

For more info about the "#FafChallenge" click here.