Chuck Liddell Training for MMA Comeback, Even In 'Big Brother' House

Chuck Liddell says he's still VERY serious about taking another MMA fight -- he's even naming names -- and kept up his training regimen inside the "Celebrity Big Brother" house ... just in case.

For the record, Chuck's 48 years old -- and hasn't had a pro fight since UFC 115 in 2010.

But he trains like a maniac -- and made it a point to keep up his workouts during "Celebrity Big Brother" because, "I didn't want to get too far out of shape."

So, who does he want to fight? He's got some ideas in mind ... but adds, "Depends on who they offer. I'm down for just about anything."

Chuck's record is 21-8 and he's widely considered one of the most iconic UFC fighters of all time ... beating legends like Randy Couture and Tito Ortiz in their primes.

Unfortunately, he was the first celeb booted from the 'Big Brother' house.