TORONTO -- Ellar Coltrane was six and had precious little acting experience when he was first cast in "Boyhood," Richard Linklater's ambitious coming-of-age tale filmed over a period of 12 years.

So when Coltrane first watched the film in its entirety, the 19-year-old could barely remember being the mischievous little boy biking around the neighbourhood or going to a baseball game with his dad.

"Things do come back a little bit. That's kind of part of what is strange about it, just how little of that stuff from the beginning I do remember. I look at this little person and I recognize myself in that seven-year-old, but I don't remember being seven," he said.

Linklater, director of the "Before Sunrise" trilogy and "Waking Life," has long been fascinated with memory and time. For "Boyhood," he reunited the cast and crew every year and shot about 15 minutes of the film at a time.

The movie follows the life of Mason (Coltrane), whose parents (Ethan Hawke and Patricia Arquette) are divorced and figuring out their own identities as adults at the same time. Linklater's daughter, Lorelei, plays Mason's sister Samantha.

Linklater anticipated that seeing "Boyhood" would be intense for Coltrane and asked him to watch it alone for the first time, the actor said.

"It was very emotional," recalled Coltrane in a recent interview in Toronto. "It's hard to really describe. It's kind of terrifying, but very beautiful and kind of comforting at the same time, I think.

"There's all these little phases and sections of your life, especially as a teenager, that in the moment, experiencing them or looking back -- like a yearbook photo -- can be embarrassing and kind of painful to re-experience," he said.

"But something about seeing it all together in context and presented as this very gradual and almost complete package ... it puts it in perspective and kind of makes it easier to see myself as a complete person, or something."

But Coltrane has watched the film many times since and still can't wrap his head around the "surreal" idea that audiences all over the globe are watching him grow up.

"I'm focusing less on myself, which I think is a much better experience. There's all the personal aspects of it and how that affects me, but I think the true meaning of the film is really beyond any of the characters or the story," he said.

"That's the conduit for expressing this exploration of the passage of time, which is how we experience time and how we interact with each other. That's really beautiful to me. I think I've learned a lot just by watching it."

As Coltrane grew older, he began to have more input into the film. He helped write a scene where he and his dad go camping, for example, and Linklater would check with him whether he'd had a particular experience for the first time -- a first kiss, a first beer.

"He didn't want me doing anything for the first time on camera," said Coltrane, although he added that Linklater was always tactful and respectful. "It was like, 'OK, if I'm talking about having a girlfriend, then I've probably kissed a girl."'

But he said his own adolescence deviated quite a bit from Mason's -- he was home-schooled and his parents were artists who were together at the start of filming. Still, he saw "Boyhood" as an outlet "to explore my own emotions as a teenager."

"I think almost everyone goes through the same kind of emotional phases and troubles as a teenager," he said. "It can be an entirely different (situation), but there's always something I can take from it and relate it to my own life and ... use my experiences to kind of flesh out the character."

"Boyhood" captures time in an unusual way. Rather than show the moments that are typically thought of as pivotal, such as Mason's high school graduation or losing his virginity, the film shows him having a beer in his robe after getting his diploma or pillow-talk with his first girlfriend.

"You grow up expecting: 'Oh my god, I'm going to graduate from high school and I'm going to be an adult, or I'm going to lose my virginity and I'm going to have all this confidence, and everything going to be awesome.' And it's not like that. Graduating is boring and sex is awkward at first. It's not this defining moment," said Coltrane.

"It's these little moments that define you and I think people really crave that. People really crave just the mundane, or at least I do. For a long time, it's been like a story is only worth telling if there's tragedy or if something fantastic happens," he added.

"There's something really comforting about having this very intentionally made thing that's not about any of that. It's just about these things that everyone experiences -- these things that aren't fantastic or cool or sexy. They're just what people do."

The Austin, Texas-born actor said he hopes to continue working in film, although he acknowledged he got lucky with his first starring role.

"I don't think I can do much better. I've had a hell of a start," he said with a laugh. "People have been kind of warning me, 'You know, most movies aren't going to be like this.' But I think that's kind of a good thing. I don't have much to strive for. It can be about the process of making films and not trying to gain success or notoriety, which is how it should be."