Keanu Reeves's 'John Wick' was originally scripted as a 75-year-old man.

The 57-year-old star has played the titular assassin in three movies so far but franchise producer Basil Iwanyk has revealed that the role had been supposed to go to an older actor.

Writing in his new book 'They Shouldn't Have Killed His Dog: The Complete Uncensored Ass-Kicking Oral History of John Wick, Gun Fu, and the New Age of Action', Basil explained: "One of my best friends is Charlie Ferraro at United Talent Agency, who sent me this script from (screenwriter) Derek Kolstad called 'Scorn'. The lead was a 75-year-old man, 25 years after being retired.

"It was the fun of watching Clint Eastwood kick ass. I thought, 'Okay, there's probably one or two names you could do this with: Clint Eastwood, Harrison Ford.'"

Iwanyk then explained how Keanu came into the picture to play the assassin.

He said: "My other best friend in the world, this guy Jimmy Darmody, is an agent at CAA, who at the time represented Keanu.

"And he said, 'Do you have any action movies for Keanu Reeves?' I remember thinking to myself, 'Keanu is one of the great action stars of the last 25 years – what happened to him? What's he been doing?' And he was directing his movie, 'Man of Tai Chi,' and doing '47 Ronin'. We give him the script, we tell him, 'Clearly, you're not 75.'"

Keanu says in the book that he instantly knew that 'John Wick' would be "such a great collaboration".

'The Matrix' actor recalled: "We all agreed on the potential of the project. It has this character of 'John Wick', but then you have also the real world, and at the same kind of underworld.

"This den of thieves that have this honour and a code. It has this emotional connection with 'John Wick', who's grieving, who's lost the love of his life and has this mythical dark past. And I loved the quest that he goes on to reclaim his life. And the world he moves through to do it."