Can you guess which Hollywood hottie put his washboard abs on full display in this eye-popping photo?

This famous fan favorite's bearing it all in a pink tracksuit ... leaving the front open -- a total slam dunk for his fans who are obsessed with his chest.

Based on his social pages, the sexy singer is known to flash an ab or two and he's gonna ride that trend till he "can't no more!"

Don't you be a meanie once you call this star by his name ... scroll through all the pics to show your love for this hell-raiser.

And, once you think you've landed on who this hot hunk is, test your skills by guessing more shirtless men in the gallery above!