Viggo Mortensen "spent weeks" learning to rock climb in preparation for his role in 'Captain Fantastic'.

Viggo Mortensen

Viggo Mortensen

The 57-year-old actor plays Ben Cash in the new drama movie and has revealed the extensive preparation he undertook in order to star as a bagpipe-playing father of six.

He shared: "We spent weeks developing the skills: rock-climbing, martial arts, yoga, things we had to do in the forest.

"Two girls had to learn how to go and skin an animal. I had to work on seeming like I could play the bagpipes and I had to learn to play the guitar so I could compose and improvise a little bit in the scenes where we play music as a family."

Of all the skills Viggo developed in preparation for the role, he admitted to being most proud of learning to rock climb.

Viggo told the Metro newspaper: "Managing to get through the rock climbing was something. I tried it a little bit before but it's something I'm not comfortable with.

"But it's worthwhile getting over your reticence or your fear of an activity. You feel better having got through it.

"Making any movie feels like a victory, especially one as complex as that with all of those kids."

Viggo stars in the Matt Ross-directed movie alongside George MacKay and Samantha Isler, and admitted he formed some strong friendships on the set of the film.

He shared: "We were like a family and we still are - I've spent time with them at Cannes and that's been great. You can't fake that if, a year later, you're still happy to see each other and you're sad to part ways again."