Jason Kelce Arm Wrestles Female Olympian, Wife Kylie Says He's a Cheater

Jason Kelce is showing off his strength at the Paris Olympics -- but not even his wife, Kylie, is rooting for him ... 'cause she says he doesn't play fair.

The retired Eagles center took on USA women's rugby star Nicole Heavirland for an arm wrestling match amid the 2024 Summer Games. The face-off took place right after Team USA won their match against Brazil ... and as you can see, Nicole was still wearing her uniform.

The 2 athletes put on quite the display ... with Jason ultimately walking away victorious as he put his arm down on the table first. However, KK was quick to suggest Jason wasn't entirely following the rules when facing off against the Olympian, saying ... "He's gonna cheat."

Nicole also playfully called Jason a cheater ... as she accused the former NFL star of holding onto the table during their contest.

Jason has since defended his win, responding to Nicole's upload ... "Holding onto something with your off hand is completely within the rules of the International federation of Arm Wrestling."

The "New Heights" podcast -- which Jason cohosts with brother Travis Kelce -- later posted the video too and thanked Nicole for letting him win ... which made it clear the whole Kelce brood is Team Nicole on this one.

Jason's visit with the USA rugby players wasn't all competition, though ... as he and Kylie also got in a sweet photo with Nicole, Kasey McCravey, Kate Zackary, Meya Bizer, and Kristen Thomas.