Assassin thriller 'John Wick' is one of the most talked-about action flicks this side of 2014, and for leading man Keanu Reeves that isn't surprising - even if we have to experience the trauma of his puppy's untimely demise.

Keanu Reeves in John Wick
Keanu Reeves has/had the most adorable puppy in 'John Wick'

Keanu Reeves plays the titular former hitman in the film, which sees him come out of retirement and set out on a brutal mission to avenge both his wife, who died some time previously, and his young pup, who was brutally murdered at the hands of some rather unforgiving rivals. The movie serves as the directorial debut of David Leitch and Chad Stahelski, whose previous filmset roles where those of stuntmen. 'I first met Chad Stahelski in 1998, he was working as a stuntman on 'The Matrix' and he worked [as the stunt double] for the character I played, Neo', Reeves reveals. 'And then I worked with him on the second two films of the trilogy where I also met [producer] David Leitch there.'

More: Early reviews were positive for 'John Wick'

With 'John Wick' having been born from such stunt-focused individuals, Reeves admits that they didn't go easy on him, enrolling him in a kind of bootcamp to get him up to scratch to play a formidable pro killer. 'I was doing judo, jujitsu, weapons training, tactical training and I also did some car driving', he says. 'It was really exciting and we were really trying to raise the bar.'

Watch the trailer for 'John Wick' here:

If early reviews are anything to go by, that bar has certainly now been raised and set, with it's Rotten Tomatoes currently standing at 86%. 'I originally went to them with the action design for 'John Wick' but I was secretly hoping that they'd want to direct it', Reeves admitted. 'Chad and Dave really realised their vision to a fresh, exciting and entertaining movie.'

'John Wick' is out in US movie theaters now.