TMZ: Aaron Carter Training with MMA Specialist Josh Polit for Lamar Odom Fight

Aaron Carter already beat Shaq. Two decades later, he's training hard to take out another NBA player.

TMZ Sports obtained footage of the 33-year-old pop singer getting ready for his three-round exhibition boxing match against Lamar Odom on June 12, and it's clear he's working hard to make improvements with MMA specialist Josh Polit.

Granted, those improvements don't necessarily make him look like a power puncher. Carter is still going to have to do a lot of work to have a chance against 41-year-old Odom, who has 10 inches and a significant amount of weight on the "Aaron's Party" singer.

Odom is a work in progress himself as a boxer, but his punches have looked far crisper in video released to the public.

"I'm pretty good, bro. It'll be fun. But you'll have fun getting knocked out," Odom told Carter in February.