Sylvester Stallone and Dolph Lundgren may be the best of friends now, but Sly didn't always love the Swedish-born karate champion.

Stallone, 72, recalled the time that Lundgren, 61, literally almost killed him while filming "Rocky IV."

“Dolph Lundgren walked in, and I hated him immediately,” Stallone said at the Cannes Film Festival (via Vulture). “I had to find a superhuman being as an opponent, someone who would be overwhelming.”

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Lundgren, a world karate champion, Stallone says was “perfect" as his sociopathic Soviet rival. "This is what I would imagine they would create as an athlete — someone who is literally perfect. Indestructible," Stallone recalled. "Shoulders, calves, forearms, giant butt, neck, back, everything.”

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While filming the classic boxing flick, Stallone almost brought upon his own demise.

“He hit me so hard he almost stopped my heart,” he said. “I told him, ‘Why don’t we just do it? Just try to knock me out. Really cut loose as hard as you can.’ That was a really stupid thing to say. Next thing I know, I’m on a low-altitude plane to the emergency room, and I’m in intensive care for four days. And there are all these nuns around.”

In a previous retelling of the incident, Stallone said the impact was similar to a car crash and said he'd been hit by "a streetcar named Drago."

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Lundgren previously told the New York Post that he had to work hard to not fight for real, whereas Stallone trained to box. Stallone's training paid off, as Lundgren says he hit harder that Carl Weathers, who starred as Apollo Creed.

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“Sly punched harder than Weathers. Weathers was all about speed and jabs,” Lundgren explained. “Sly was more about hooks. I was actually pretty surprised at how well Sly could fight. I fought for real and had to learn how to fake it! He was really committed.”