The actors will join Bruce Willis, Arnold Schwarzenegger and producer Sylvester Stallone in the follow-up to the action film.
Stallone told Entertainment Weekly: "We'll have a big showdown between me and Van Damme, which has been anticipated for a long time, so it should be a good one."
The actor, who will not be directing the follow-up, hinted that he would be adding more action stars to the mix.
"We're trying to work out different scenarios. I like using people that had a moment and then maybe have fallen on some hard times and give them another shot," he said.
"So we're always looking for actors like Michael Biehn and Michael Pare. I like those kinds of guys. Someone did it for me and I like to see if I can do it for them.
"We also need some new blood in there, a Navy SEAL-type, because with the Expendables none of them have 20-20 vision anymore. They need some help, man."
Nicolas Cage and John Travolta are also rumoured to be interested in joining the cast.
Stallone added of Travolta: "It's possible. The one thing I've learned is what is a fact on Monday is a complete fallacy on Tuesday. A lot of it is scheduling.
"It's not financial. It's just that Bulgaria is definitely a jaunt. It's a commitment, you know what I mean? Especially in the dead of winter."
Con Air's Simon West is taking over directorial duties on the second film.
Jason Statham, who will reprise his role from The Expendables, revealed this week that production will start in Bulgaria by the end of the month.
Watch the trailer for The Expendables below: