Stallone, who stars alongside his former bête noire in the new thriller Escape Plan, described a fiercely competitive relationship with the musclebound Austrian-born star which drove both on to greater success.
"We had violent hatred," the 67-year-old actor told US talk show host David Letterman. "Have you ever had that ever? Competition where you really had an arch enemy that kind of brings out the best in you. As Arnold would say, it really pushed you to accelerate."
Stallone said the antipathy between the pair went so far that he hated "that [Schwarzenegger] was on the planet, basically". He said: "After a while, I started to like this competition, this one-upmanship. He'd get a bigger gun. I'd shoot more people. He'd shoot more people. But then, he went into science fiction, which kind of left me behind."
Stallone entered the public consciousness via 1976's Rocky, the tale of an unlikely blue collar championship boxing contender which he starred in and co-wrote. Schwarzenegger was best known for the 1977 docudrama Pumping Iron, but did not really become a well-known action star until 1981's classic fantasy Conan the Barbarian.
The pair have since starred together in The Expendables series of action films, as well as Escape Plan, which sees them as cellmates vying to find their way out of a maximum security prison that has been designed by Stallone's structural engineer character, Ray Breslin. Schwarzenegger plays a character named Rottmayer. Mikael Hafstrom's film, which was previously titled The Tomb, hits US and UK cinemas this weekend, before debuting in Australia on 28 November.
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