Via TMZ: TMZ spoke with Randy's brother, Lanny Poffo, who tells us the wrestling legend suffered a heart attack while he was behind the wheel around 9:25 AM ... and lost control of his vehicle.
Earlier this month, Savage celebrated his 1-year anniversary with his new wife Lynn.
Savage was 58.
Macho Man began wrestling in the WWF in 1985 and became a superstar with his trademark catchphrase "Ooooooh Yeaahhhhh." Savage was so popular, he became the spokesperson for Slim Jim in the mid '90s ... and became virtually synonymous with the brand.
UPDATE: Florida Highway Patrol tells TMZ ... Savage was driving his 2009 Jeep Wrangler when he veered across a concrete
median ... through oncoming traffic ... and "collided head-on with a tree."
Rest in Peace.