In describing the upcoming Rambo movie, Sylvester Stallone called it “a feral beast.”

The Hollywood actor, who recently admitted to working on a fifth film in the high-action franchise, has revealed that the forthcoming final installment (titled Rambo V: The Savage Hunt) will be different from the previous movies and filled with “unadulterated rage.”

“It’s not a super-soldier, it’s a feral beast—a thing. It’s this amalgamation of fury and intelligence and pure unadulterated rage, from before men became human - it’s inhuman! It’s man’s “conscious” fighting his dark, uncontrollable unconscious. It has absolute cunning and intelligence and a will to survive that is only matched by Rambo’s.”

The movie will see the 63-year-old actor reprise his role as Vietnam veteran John Rambo next year as his character battles drug and people traffickers on the US-Mexico border.

Rambo, released in 2008, had initially been billed as the final installment in the series. It was recently revealed Sylvester, who first played John Rambo in 1982’s First Blood, was struggling to get into shape for the part.

A source revealed, “Sylvester really had to push himself to get in shape for the last film and knows he’ll have to do that again for the next movie. It doesn’t get any easier the older he gets.”