Chuck Liddell's got a message for all the big-name boxers trying to transition to MMA ...
DON'T DO IT -- unless you wanna embarrass yourself.
The Iceman ain't throwin' shade at Berto ... he's just keepin' it real on guys pulling a reverse Conor McGregor ... cause it's A LOT harder to go from boxing to MMA.
If Conor fought Floyd Mayweather in a non-boxing match, for example ...
"Floyd wouldn't have made it out of 1 round -- not kickboxing, not MMA, not a street fight -- not 1 round," Liddell said.
Chuck did have an important piece of advice for boxers trying to make the switch ... but he still thinks it's a bad idea.