Supa Hot Fire

Ray J is learning from the best as he prepares for his upcoming MMA fight against Supa Hot Fire ... because we have video of him training with MMA icons Chuck Liddell and Rampage Jackson. "The Iceman" -- with an impressive 21-9 record -- got to teach the singer a thing or two about what he'll…

Ray J, as you know, was recently on death's door with a bunch of serious health issues — but now the R&B singer is back and stronger than ever, training his ass off for his upcoming MMA fight against Supa Hot Fire. TMZ obtained exclusive video of Ray getting into tip-top shape with his…