54-year-old Mike Tyson says he would fight 30-year-old, 6'6", 240 lb. heavyweight champion Anthony Joshua, RIGHT NOW ... as long as the money went to charity!!
Some background ... Rafael Cordero, Mike's legendary trainer recently told us that Tyson -- who last fought in 2005 -- could hang with beasts like Joshua, Deontay Wilder, and Tyson Fury.
So, when "Iron Mike" joined the "TMZ Sports" TV show to talk about his HUGE Legends Only League fight with Roy Jones Jr.