Sly Stallone talks Grudge Match

Stallone talks about his upcoming movie on "Good Morning America." Donna Svennevik/ABC/Getty Images

ON CHRISTMAS DAY, "Rocky" meets "Raging Bull" in "Grudge Match," a boxing film starring the men who gave us the two most iconic characters in the hallowed history of the boxing movie genre, Sylvester Stallone and Robert De Niro.

Their comedic wink at the audience, from director Peter Segal ("The Longest Yard"), tells the story of Billy "The Kid" McDonnen (De Niro) and Henry "Razor" Sharp (Stallone), two prune-skinned, '80s-era, prizefighting rivals who are coaxed back inside the ropes for one last shot at supremacy, even if it means flashing some flab and a few wacky veins from the ring.

Recently, Blitz caught up with Sly to discuss his return to the ring, squaring off with his legendary co-star and the sport that keeps him coming back for more.

Sam Alipour: Jake LaMotta and Rocky Balboa in one ring. How did this one come about?
Sylvester Stallone: It was the idea of the filmmakers, the producers. This is never going to happen again. Robert De Niro and I opened up in the same little crappy theater complex in New York, "Taxi Driver" and "Rocky." I mean, boom! We've been like this our whole careers. Then I went here, he went there. And now, here we are again. And as fighters? What are the odds of that? It's pretty remarkable. "Rocky" wins an Oscar. "Raging Bull" wins an Oscar. "Raging Bull" has one of the greatest performances of all time. And now they're fighting? Give me a break. That's an event. I want to see that. So this is the unofficial "Rocky VII" or "Raging Bull II."

Alipour: It takes guts for an actor to do a send-up of an iconic character from their filmography. Are you at all nervous about the audience's reaction?
Stallone: I was nervous about it. I didn't want to do it at first. I thought it was just going to be a parody, which it is in some ways. There's no way to get around that. And there's no way of just cross-referencing "Rocky" and "Raging Bull." And then I thought well, maybe that's a good thing. Since those films have pretty well gone the way of extinction, this is some way of realizing them again. Movies are enjoyable, but they're not sacrosanct; they're not sacred cows. Here we are in the magical world of boxing where "Rocky" is fighting "Raging Bull." I mean, of course, no one's under any illusions that it's anything other than that. This is the beauty of fantasy. These guys can go back and correct something in their life and make it fulfilled.

Alipour: It's clear you're very fit, still, but let's face it: you're 67. De Niro is 70. How did you men prepare for the physicality of your roles?
Stallone: Bobby had to get in shape on the East Coast and I was on the West Coast. We didn't have the opportunity to work out together. We had this trainer who was great, Bob Sally. Then we got together for a couple of days and it all worked out. Bobby is lighter than I am, so I had to come down to 168 pounds. I haven't been that since 1981. It's really thin. I mean, thin. So I went onto a diet where it's almost 95 percent protein; I don't recommend it for most people unless you're on a mission to do something. I had to wait until about three days before the fight for what we know as "carbo load," which means to eat all the good stuff. And Bobby is on a different mission. I said, "Hey, those Oscars are not doing you much good now, are they pal? Welcome to Rockyland."

Alipour: Was there ever a hint of competition between the two of you during filming?
Stallone: There was no rivalry. Together, when we're in the ring, we're about a combined 140 years old. Most fighters are, together, a combined 44 years. [Laughs.] So that's remarkable, too. And I think men never grow up -- never. I never thought we were going to have any problems, but I had to factor in we're not in our primes. We're not speed demons. We're clumsy. We're a little arthritic. We were both punchers, and each of us, Bobby and I, has our strong suits, the way we throw our punches. You have to be sensitive to that.

Alipour: You've now given us seven boxing films and an eighth, the "Rocky" spin-off, "Creed," is reportedly on the way. What is it about the sport that repeatedly has you going back to well?
Stallone: I've always loved the sport. I did a little amateur boxing. I love boxing and the metaphors about it. There's a real classicism where it breaks down to a man's athletic ability coupled with his courage. The two don't always go hand in hand. I'm always watching the character more than the punches. I've always been fascinated about a man going against another man. You see what a person is made of under duress. It's what's in here [points to heart] that fighting is really all about. And I go, "Ah, that's it. I can work with that." During filming, I'd look back at the monitor sometimes and I'd flash back to all of this, my entire career.

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