The Terminator star is not sure how he injured himself, but he explains it comes from too much physical activity.

"It's just a little stress fracture," he told Live! with Kelly on Thursday (15Dec16). "You could get it from too much skiing, too much squatting, too much running or too much bicycling."

The 69-year-old has to wear the brace for a few weeks, but he has revealed he will not be following doctors' orders.

"I'm going to replace it very quickly with ski boots," he said. "Next week I'm going to go up to Sun Valley skiing, so I think a solid boot instead of this. Same thing, it keeps the leg stable and I get to do some skiing."

Arnie will kick off the New Year as President-elect Donald Trump's replacement on U.S. reality show Celebrity Apprentice.