Evander Holyfield is just a few weeks shy of his 57th birthday ... but he's still ready to throw down -- and will fly to Japan for a charity exhibition in 2020.
Holyfield hasn't fought professionally since May 2011 (he beat Brian Nielsen) -- but "The Real Deal" says he's kept himself in prime shape ever since and he's ready to get back in the ring.
The details about the exhibition fight are unclear but Holyfield says he still thinks he's got the at signature knockout power.
Don't get it twisted, Holyfield says the goal is to raise money for people in need -- and not to annihilate his opponent -- so the bout will be more of a performance than a no-holds-barred fight.
"The big thing is to give people in Japan the opportunity to see the only 4-time heavyweight champion of the world."
In related Holyfield news, Evander's 21-year-old son Evan "Yung Holy" Holyfield is about to make his pro boxing debut on the undercard of the Canelo Alvarez vs. Sergey Kovalev fight.
Evan is taking on Nick Winstead in a 4-round junior middleweight matchup.
"Yung Holy" previously told TMZ Sports he thinks he can be better than his Hall of Fame father.
"My dad always tells me every generation gets better. It's pretty much easy to believe, number one it's in the bible, and the bible don't tell no lies."