Mystery Benefactor Saves Octomom's Firm Ass

Nadya Suleman just got a serious spot from someone at the gym she was recently banned from -- someone committed to saving her body through the power of money.

TMZ has learned an anonymous benefactor rolled through a 24 Hour Fitness location in L.A. Wednesday afternoon and threw down enough cash to pay for a one-year gym membership for Octomom ... since she apparently couldn't afford to pay it herself.

As we first reported, Octo was cut off from the gym after she fell behind on her membership fees three separate times.

No word if the mystery man will spring for a sitter to tend to the 14 kids while Nadya continues to tend to herself.