Warren Sapp let it all hang out for his special day ... stripping down to a skimpy mankini and showing off his birthday bod!!
The Hall of Fame defensive tackle turned 49 years old on Sunday ... and kickstarted his next trip around the sun with as minimal clothing as possible.
"49 never felt so Good since I wore it at Apopka!," Sapp said on Instagram ... referencing his old high school number. "#HappyBirthdayFatBoy"
Warren wasn't only wearing the banana hammock -- he made sure to have a diamond chain on as well.
Of course, Sapp was one of the greatest players of his time -- he is a Super Bowl champ, 4-time first-team All-Pro, 7-time Pro Bowler, and was named to the league's All-Decade teams in the 1990s and 2000s ... so he's definitely got a lot to celebrate.
Enjoy the birthday, Warren!!