Britney Spears' ex-husband Kevin Federline has brushed off rumors his upcoming TV weight loss challenge is a direct result of doctors telling him to drop the pounds or face serious heart problems.

The 31 year old, who was once an athletic back-up dancer for Spears, has become tabloid fodder in recent months for packing on the pounds, and now he has signed on to lose weight on the new season of reality show Celebrity Fit Club.

But he insists the decision to join ex-girlfriend Shar Jackson on the show had nothing to do with health concerns - and reports his ballooning frame has sent his blood pressure skyrocketing are not true.

His spokesperson tells People magazine, "The rumor (of potential heart problems) is 100 percent false. He's focused on taking care of the kids and is (already) eating healthier and losing weight."

See more photos of Kevin Federline here!

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(This news article provided by World Entertainment News Network)