Cannes: Former box office titans Sylvester Stallone and Arnold Schwarzenegger may have joined forces on screen, but at the press call to promote their new movie, The Expendables 3, neither could resist a snipe at the other’s less celebrated back pages.

The pair – who joined an all-star cast, including Harrison Ford, Mel Gibson and Antonio Banderas at the Cannes Film Festival on Sunday to promote the new film – were addressing questions about their infamously competitive past, when Schwarzenegger, 66, reacted to the 67-year-old Rambo star referencing his iconic line from The Terminator, “I’ll be back.”

Best mates or bitter rivals after 20 years? Sylvester Stallone and Arnold Schwarzenegger promoting The Expendables 3 at Cannes. Credit:Yves Herman

“I always wanted to be in that movie that Sly did, Mama Don’t Shoot,” the Austrian cooed back snidely, referencing Stallone’s ill-fated 1992 cop comedy, Stop! Or My Mom Will Shoot, which the star himself declared his worst ever picture. “I love that movie, because I saw Sly in diapers,” Schwarzenegger added, to the delight of the press.

Not one to give ground, Stallone quickly fired back, “Wait, didn’t you have a baby in Junior?” in reference to Schwarzenegger’s critically panned 1994 comedy, in which he stars as a male scientist who has a baby. “I saw you give birth [in that film].”