United Kingdom, April 24 -- Arnold Schwarzenegger's rivalry with Sylvester Stallone was "very helpful" to their careers.

The action stars had animosity towards one another at the height of their success in the 1980s and 90s but admitted having someone they could view as "competition" proved to be a great motivator in their work.

In a joint interview for 'TMZ Presents: Arnold + Sly: Rivals, Friends, Icons', Schwarzengger, 76, said: "There's no two ways about that: He was very helpful in my career because I had something that I could chase.

"[I was] the one who started this whole thing ... by opening up my mouth, saying stupid things, being competitive."

Stallone, 77, added: "[When Arnie] came along I was like finally, something to moti...