The actor, who plays Tony Stark's (Robert Downey Jr) friend Rhodey in the film, revealed that the suit will be a source of tension between the two companions.
"We've got a private sector and a public sector, or rather a military version of Iron Man," Cheadle told MTV News.
"And I think there is a desire from the powers that be to make sure that those things are distinguished and distinguishable so that we know where everybody stands," he continued.
"I think that's kind of the tension that is created for Tony and for Rhodey, because like who's really got the stick, and who really gets to decide what happens in certain situations? And that's what will be a lot of fun to explore in this film too."
In June, it was reported that the Iron Patriot would not be featured in Iron Man 3, but rather that the on-set shots of a man in armour show War Machine's new costume design.
Iron Man 3 will open in theatres on May 3, 2013.