Blac Chyna & Rob Kardashian Getting Sweaty Together

1/26/2016 8:18 AM PST

Blac Chyna and Rob Kardashian Getting Sweaty Together

EXCLUSIVE

Rob Kardashian and Blac Chyna have been getting hot and heavy in more ways than one.

Sources close to the unexpected couple tell TMZ, Chyna has been a positive influence on Rob because she's helping him get back in shape.

But don't get it twisted ... we're told they're definitely more than just workout buddies -- the romantic relationship is fairly recent, and things are more playful than serious.

We're told Chyna introduced Rob to her personal trainer about a month ago, and since then they've done several intense workouts together. With and without the trainer, we're guessing.