41-year-old Odom will take on the 33-year-old Carter at the Showboat Casino in Atlantic City on June 12 in a 3 round exhibition, Celebrity Boxing honcho Damon Feldman tells us.

Besides the age difference ... there's a significant height differential -- Odom is 6'10" and Carter is 6'1".

Odom obviously has a background as a professional athlete -- playing 14 seasons in the NBA.

He nearly died in 2015 from an overdose at a Nevada brothel -- and subsequently suffered several strokes and heart attacks. Some doctors didn't believe he'd fully recover.

Miraculously, Odom beat the odds and returned to the basketball court during a short stint with the BIG3 league in 2019.

Now, he's turning to boxing ... where he hopes to put a beating on Aaron Carter, who's also struggled with addiction. He sought treatment in 2017.

Both men have been busting their asses in the gym and we're told they're taking the fight very seriously ... no one wants to be the next Nate Robinson!

Sure, Aaron might appear to be the underdog -- but Carter tells TMZ Sports he "grew up street fighting" and he's ready for the challenge.

Damon Feldman -- who's been behind a ton of celebrity boxing events over the years -- says this fight has real potential to be the best one yet.