Andre Berto is totally down to take on the winner of a fight that doesn't exist yet ... saying he'd gladly take on the victor in the Canelo Alvarez/GGG mega-fight ... if it ever happens.
We got Berto out in Beverly Hills and asked him about the fight ... which is the second biggest dream fight out there (Mayweather/McGregor #1) and who he thinks would take it.
Berto -- a former world champ says he thinks GGG would be too much for Canelo but who ever wins .