. The last time we saw robert de niro and sylvester stallone, in a movie together, was when they sparred in "copland." The movie's name is "grudge match." Take a look at a scene. If we don't sell... See More
. The last time we saw robert de niro and sylvester stallone, in a movie together, was when they sparred in "copland." The movie's name is "grudge match." Take a look at a scene. If we don't sell tickets, we don't make money. No tickets, no money. I'm in. No ticket, no money. No money, no fight. No ticket, no money. No fight, no money. No tickets. All three ways. No tickets, no fight, no money. No money, no fight, no tickets. What's the third one? All three ways. What's your problem? My problem is, you fight you fight. You have to do these things. The point I'm making is if we're going to do it, we have to do it together. Okay. I'm telling you, scenes like this, over and over again, in this film. So thrilled to have sylvester stallone and robert de niro, here on "good morning america." Welcome. What was your thought when this idea came up? First, I was a little reluctant to do it. I don't know if I want to do a parody on "rocky." Why were you so game to do it? It wouldn't be anybody but him. It's "raging bull" meets "rocky." It's brilliant. It's been 33 years since "raging bull." I've done some boxing. But not much. But it gave me an excuse to really do it. My house is built like a ring. Hey. Welcome to sly land. It was against my -- I would have assume you would have been like, I love boxing so much. I have the worst taste. I said, all these -- forget it. No matter what, I'm always behind the curve on what's good for me. Great to have friends like robert de niro. Can this guy really throw a punch? Yeah. I'm not as well as him. But he's got friends, too. You know? Little this. Little that. "Raging bull," "rocky." What a treat to see you guys sparring verbally. It's working with robert. He's so accommodating. He's so easy to get along with. He knows his craft. I think you have a career. Yeah? It's starting up. But you got it. You're going to be around a while. Thank you so much. Everybody here loves it. It's called "grudge match," in theaters christmas day. Really a pleasure.
This transcript has been automatically generated and may not be 100% accurate.