From New Moon to East LA, Harry Guerin talks to the director of the new drama A Better Life.

Sex-obsessed teenagers trying to break their ducks; a comedian who comes back from the dead; a lonely misfit with a suicidal mum and a tosser of a confidant; an orphan's adventures in another world; the love between a teenage girl and a 104-year-old vampire and an illegal immigrant trying to live the American dream - like some old school director, Chris Weitz has covered a lot of bases in his six films to date. Together with co-director brother Paul, he found box office gold with American Pie, followed it up with another comedy, Down to Earth, and in 2003 shared an Oscar nomination for the script for their take on Nick Hornby's About a Boy. Without Paul, Weitz then went on to direct two sacred cow blockbuster adaptations in a row: The Golden Compass and The Twilight Saga: New Moon. Now he's made A Better Life, his most moving film since About a Boy and one which deserves to gets its star, Mexican actor Demián Bichir, an Oscar nomination - at the very least.

Mixing family drama with social commentary, the film's working class hero is Carlos Galindo, a Mexican gardener in Los Angeles who's trying to keep his teenager Luis (José Julián) on the straight and narrow, stay one step ahead of immigration officials and buy his soon-to-retire boss' truck so that he can keep the customers. In an LA odyssey, father and son get to see a different side to each other on one fateful day. If you're lucky enough to see the movie, you'll get a masterclass in how one actor can make a character so completely his own that you can't imagine anyone else on the screen.

"He was the first person and really the only person," Weitz says of casting Bichir. "You could think of names like Benicio Del Toro or Javier Bardem, but, to me, it was an extra benefit to have an extraordinarily talented actor who had not been seen many times before on American screens, because it's a film about someone who is relatively unknown and ignored in society. If you were to see a face that was very familiar to you, you're bound to bring all kinds of baggage with it. Whereas especially for American audiences, they get to discover this character and actor at the same time. And it's quite an astonishing experience. Every once in a while this happens - like with Christoph Waltz in Inglourious Basterds or the first time people saw Javier Bardem. They realise that there are these tremendous actors around the world who, when given an opportunity, absolutely dazzle."

Such is the authenticity of Bichir's performance that it will be hard for some viewers not to think of their own fathers while watching him - of sacrifices made, opportunities missed and the failings and triumphs of the man behind the authority figure. From the moment we see Carlos wake up at dawn on a couch in his work clothes and head out for another day we're on his side, and his attempts to connect with the wayward Luis in the few minutes when they're in each other's company make for heartbreaking viewing.

"It's not all the son's fault, either," stresses Weitz. "I think that Demián's character doesn't really have the emotional equipment to express himself to his son, and I think that's true of a lot of father-son relationships. It's only by observing that a son can get to know his father, because men are often inexpressive about their emotions and what they've gone through - at least in more traditional cultures. The movie is in many ways the story of these two men understanding one another, or trying to understand one another.

Indeed, although Weitz' CV is eclectic, study it a little harder and you see that relationships between fathers (or surrogate fathers) and children is not a new departure for him. Remember Jim and his right-on dad in American Pie, or Marcus and Will grappling with each other's complexities in About a Boy?

"I used to put that all on my brother and think that he was obsessed with father figures," he laughs. "But actually, when I think about it, my father was an emigrant; he was considerably older than my brother and I and had been through a different time period: he had fought in the Second World War. So, it's taken a long time for me to understand what he went through - the sacrifices he made in order to make life better for us. Father figures play a big role in both my movies and my brother's."

Apart from allowing Weitz to continue this theme, his new film also sees him connect with other sides of his family, namely his mother's and his wife's. Weitz' grandmother is the 101-year-old Mexican actress Lupita Tovar, while his wife, Mercedes Martinez, is Cuban-Mexican. "My grandma came to America when she was 17, but I'm the first generation in my family not to speak Spanish. I'd been looking for an excuse to start learning for quite a while - to get back in touch with my heritage a bit - and to work in Mexican LA with a bilingual crew was a tremendous opportunity for me to learn. I learned that I had to ask a lot of questions! I've made six movies now and become more and more confident in my abilities to get things across on screen, but this was a case where I really needed to ask a lot of questions - and admit that I didn't know about things in order to understand the environment in which I was working. Otherwise, the whole movie was going to be a sham; I would just be this guy making a movie about a bunch of received ideas. Without talking to ex gang members, without talking to teenagers from East LA there was no way this film was going to get made on my part."

From real barrio locations to extras, Weitz did his homework very well, and A Better Life reveals greater powers as a drama director than some critics may have been willing to acknowledge in the past. That said, the experience hasn't been some kind of career epiphany, and he doesn't have a problem with doing a film with a lot more zeroes in the budget figure in the future.

"For me, A Better Life is just in keeping with I've always done, which is to try to do something different every time - I try to stay a moving target. It's not that I have a particular love for smaller films or for bigger films or anything; it's just that I wait for the next script that I feel I have to do, otherwise I'll regret it. Until that next film comes along I will just sit around."

"Sitting around", as Weitz puts it, is way wide of the mark. When he's not on set as a director-producer, he's working as the latter, bringing the likes of Nick and Norah's Infinite Playlist, A Single Man and the upcoming American Pie 4, American Reunion, to screens. Right now, however, awards season is looming, and Weitz has one thing on his mind.

"To be honest, I'm more busy trying to get this film out than I am working on American Pie 4," he laughs. "Demián's performance is the standout thing about A Better Life that may serve as a kind of bait for more and more people to watch it, because it's really something special. He's deserving of a nomination, I think, and that's my job from now: to push him. People need to see this kind of talent."

Make sure you're one of them.

A Better Life is in cinemas now.