Shot over 12 years, Richard Linklater's new film Boyhood is being called the best movie of the decade. Its cast members have been out talking about the experience.

BoyhoodCo-stars Ellar Coltrane and Lorelei Linklater in 'Boyhood'

Ethan Hawke, who plays the family's father, has made eight films with Linklater. He commented on the uniqueness of this project: "We see very dramatic portraits of terrible parents or stereotypical good parents, but you don't see them both at the same time very often: parents struggling to be good parents, failing sometimes and succeeding other times, much like our own parents and ourselves. [Linklater] thinks life is pretty dramatic and beautiful and exciting as it is. For me, that's kind of revolutionary."

More: 'Boyhood': Luck, Innovation And Bundles Of Talent Mean Cinematic History Will Be Made This Weekend

Ellar Coltrane filmed his first scenes as Hawke's young son Mason when he was just 6 years old. "Around 12 or 13, it began to gradually dawn on me what was actually happening," he said. "Later on, the character started to merge with my actual life, and it became much easier."

By contrast, Linklater's daughter Loreilei, who plays older sister Samantha, once asked her father to kill off her character. "Yeah, towards the middle years I didn't like acting as much," she admitted. "It just wasn't what I wanted to do the most. Later on I took back to it and decided that I actually really like acting. There's some part of it that really does speak to me. It's somehow therapeutic."

Playing their mother, Patricia Arquette has enjoyed audience reactions. "I've had people come up to me and say, 'Oh my God, you age so beautifully in this movie! And then some people will be like, 'How does it feel to watch yourself not be the hot girl anymore?' It says a lot more about them and their perception, but that's the great thing about getting older and that's the great thing about being around the block 100 million times by the time this film comes out."

Linklater admits that he played off events in the real world as he developed the script from year to year. "I was collaborating with Ethan, Patricia and the kids who, as they matured, become even more collaborative," he said. "Even though I had a contour for this movie, it was always going to go where they went. If he grew up to be a wrestler, maybe that would have worked its way in."

More: Richard Linklater's 'Boyhood' Premieres First Trailer To Show A Film 12 Years In The Making

Linklater also believes that the film has a universal appeal beyond its American setting, and critics have agreed. "There's something about the film that taps the commonality of the human maturation process, and parenting too," Linklater said. "I had a guy from Africa tell me, 'Oh, it kind of explains my dad to me!' That's what we do when we observe art, we take it in and adjust it to our own lives."

Boyhood has won awards at festivals and opens across the US and UK this weekend.

Watch the trailer for 'Boyhood' here