"It ain't over till it's over," says Sylvester Stallone, who stopped by "Good Morning America" today to talk about his latest movie, "Rocky Balboa."
It opens on Wednesday.
It was the original "Rocky" movie that earned Stallone an Oscar in 1976 and launched his career.
The 60-year-old will continue to put up a good fight in this, the sixth installment of the series.
In the new film, scarred with arthritis and aching joints, Rocky has been reduced to telling stories in restaurants about his exploits, but decides to mount the stairs one last time to fight a younger boxer.
"Part of the story is it really is not over," Stallone told Diane Sawyer on "GMA." "Yeah, [fighting] hurts a little bit more, but you can do it."
In 1976, life imitated art when "Rocky," a little sleeper of a film found blockbuster success starring Stallone, an actor no one knew.
A forceps injury at birth had damaged part of Stallone's face and tongue, giving him a speech defect.
He had been in and out of trouble as a kid and reportedly had $100 in the bank when he wrote the story of a boxer with a giant heart.
When Stallone initially tried to get the sixth film made, Hollywood was skeptical. Some even called him a has been.
"The new Hollywood is pretty straightforward," he said. "They were sensitive about it and said, 'Over our dead body.'… New Hollywood is a business."
The original "Rocky" garnered an astonishing 10 Oscar nominations.
At the 1976 Oscars, boxing legend Muhammad Ali appeared on stage with Stallone, joking that he had stolen his story for "Rocky."
Stallone said that Rocky's rival Apollo Creed was taken "quite liberally" from Ali.
The lesson of the new movie is about keeping your dreams alive, even as you get older, Stallone said.
"The older I get, the more I realize the harder it gets," he said. "When you're older, it's the loss of things. … And it's dealing with the sense [that] things are disappearing. … And how do you keep that flame inside."
Like the first film, "Rocky Balboa" was written by Stallone who said that he felt it was partly autobiographical.
"I sort of lived it so it was nice to be able to get it on film," he said. "Can you go back and correct wrongs? … That's the dilemma. … It's the regret that builds up and eats at people."
"It ain't over till it's over," Stallone's signature character tells a younger boxer in the film.
"What's that? From the '80s?" the boxer replies.
"No, actually. I think it's from the '70s," Balboa says.
Rocky's training ground was the steps of the Philadelphia Museum of Art, a must-see tourist attraction.
Stallone became one of Hollywood's hunkiest movie icons, going on to star in other hit films, including "Rambo" and "Cliffhanger."
Many people remember Stallone's character fondly.
"I grew up on 'Rocky.' It was amazing," one man told ABC News. "My mom and dad went to see the first one when they were dating."
"I think the concept of 'Rocky' is the story of an American hero -- people that come from adversity and rise above it," another woman said.
Saying farewell to "Rocky" will be tough, Stallone said on "Good Morning America."
"You gotta say goodbye forever. … It was a big deal," he said. "And I'll never have that kind of character again."