Busta Rhymes is busting out with a thirst trap, showing off his jaw-dropping transformation in all his shirtless glory -- and those abs are proof of the dedication he's put in!

This new look didn’t happen overnight -- sources close to the rap legend tell TMZ Hip Hop the 52-year-old has shed an impressive 64 pounds since last fall, all thanks to a major lifestyle makeover.

Busta’s dedication is next level -- sources tell us he hired a traveling chef to keep his diet on track while on tour. Plus, he's been hitting the gym hard to keep that evolution going strong.

His new regimen isn’t just shaping his body -- it’s shaping his career too. With a killer physique and renewed energy, he landed a major Christmas Walmart campaign this holiday season.

And the hits keep coming ... he's gearing up for a spot on "The Tonight Show Starring Jimmy Fallon" later today to promote his upcoming album, "Dragon Season," dropping January 10.