Arnold Schwarzenegger joked about having a bigger knife than Sylvester Stallone as he wished him luck ahead of the opening of his new Rambo film.

The former California governor posted a message on Twitter to his 80s action hero rival, wishing him luck for Rambo: Last Blood but teasing that Stallone’s weapon is no match for his own.

The clip shows Schwarzenegger with a knife autographed by the Rocky and Rambo star.

He says: “Sly, I just saw your knife that you have signed for charity in Cardiff.

“It’s unbelievable, look at this knife.”

But he then pulls out a much larger knife with his own name on it, saying it was from his 1987 film Predator.

“This is not a knife, this is a knife,” he laughs.

“This is what we used on Predator, it’s just a little larger than yours.

“But don’t worry about it.”

Sylvester Stallone
Sylvester Stallone stars in Ramgo: Last Blood (Dominic Lipinski/PA)

He adds: “In all seriousness, all the best of luck with Rambo this weekend ok?

“You are gonna be a hit, it’s gonna be a smash – you are the best.”

The caption for the post says: “Good luck with Rambo this weekend, @TheSlyStallone.

“I loved it, and when it’s a hit I’m going to buy you a new knife to celebrate.”