‘Speed Racer’s’ Racer X is revealed to be Matthew Fox

WHEN imagining a chance encounter between actor Matthew Fox and, say, a father and his grade school son, one would probably peg the dad as the one having the glint of recognition, making the awkward approach and perhaps pleading for some hint about what’s coming up on “Lost,” the twisty, freaky, grown-up TV drama that has starred Fox for the last four years.

A few weeks ago, though, Fox saw how the future of that fan equation might look after he caught an advance screening of his new movie, “Speed Racer,” the Wachowski brothers’ long-awaited film adaptation of the iconic Japanese cartoon series from the late ‘60s.

“I’ve never done anything that kids can see,” Fox says. “And in the bathroom afterwards, this little boy was talking to his dad like, ‘It’s so awesome! We have to see it on Imax, Dad!’ And he was tying his shoelace, and I said, ‘Hey, how old are you?’ ” Here, Fox reenacts the boy’s slow head lift, mimics his nonchalant response: “ ‘I’m 8,’ ” and then the widening eyes as he looked up and whispered in awe, “ ‘You look like Racer X!’ ”

The 41-year-old actor laughs at the memory of it, with the glee of someone as excited as that boy who got to meet the candy-colored family flick’s mysterious, masked avenger/protector. “That was a really cool moment for me and a big part of why I wanted to be a part of it, you know?” says Fox. Watching his own kids -- Byron, 6, and daughter Kyle, 11 -- experience the movie they’ve been anxiously awaiting since Fox was cast over a year ago will be “an absolute highlight of my time in this business,” he says.

What Fox’s kids later saw on screen at the movie’s premiere was their father maneuver a physics-defying fantasy car and waylay bad guys, all in the name of saving Speed Racer (Emile Hirsch) from evil on the road and corruption in the sponsorship world. What Fox had to do on Berlin sound stages last year to achieve this, though, was to hone the art of green-screen acting and train intensely for martial arts sequences while wearing a skin-tight leather racing suit and eye-shielding skull wrap.

“When you take on something like this, which I was incredibly excited to do, there are nights lying awake in bed where you start to think there are so many ways it can go wrong,” he says. When asked to elaborate, Fox says, “Just not pulling it off. Your job as an actor is to convince, to find some sort of truth in it. You have to believe, and then your belief in it will be contagious.”

The jaw for the part

But when Fox stepped into the role after the Wachowskis’ “Matrix” man, Keanu Reeves, proved unavailable, producer Joel Silver says, it was as if the anime/digital/live-action hybrid suddenly had “verisimilitude.” “He really has that square-jawed look of a superhero,” says Silver. “He did a great job. He really roots the whole picture.”

That’s not an easy task when a movie that takes place in different locales all over the globe is actually filmed on a sound stage. But Fox credits the Wachowskis with doing all they could to help the actor by sharing the previsualization technology that allowed the cast to see its digital environment before shooting. “They would capture a rehearsal,” Fox explains, “then you could go around to these huge plasma monitors and there’d be guys with computers laying in imagery around what you’d just done. You could see yourself within the context of the world. I felt I was in the greatest hands.”

Aside from the bones-jostling gimbal used for the racing scenes (“All you were doing was hanging on,” he says), the climactic fight sequence was the toughest two weeks of the shoot for Fox, whose natural athleticism -- the Wyoming-raised Fox played football in college -- led the stunt guys to believe he didn’t need a double.

But despite wearing a stretchier version of his form-grabbing costume, the physicality ensured glitches. “A couple of times the crotch ripped out,” he says, smiling. “The minute you start sweating in leather, it just clings to you, so movement was difficult. The visors would fog over on the inside. So moments into fighting, I wouldn’t be able to see. I hit two stunt guys, which I felt really bad about. But they were super cool. The thing you learn about stunt guys is it’s sort of a badge of honor for them.”

Fox had such a blast making the movie, he’s ready to return for any potential sequels. “I would so love to get back into that world again,” he says. But the only plans he has for his “Lost” hiatus is a summer in Oregon with his wife of 15 years, Margherita, their kids and his two brothers’ families. “We’ve all been talking about how we’ve got to get closer so [our children] can have those really good first-cousin relationships,” he says.

As for that Hawaii-filmed TV series “Lost” that takes up more than six months of his year, Fox is still thinking about the creative momentum that’s come with this season’s post-island flash-forwarding (“a genius move,” he says), a set end date (two more seasons to go) and deepening Dr. Jack Sheppard’s fractured hero-complex. “Jack’s one thing in life has been to get off the island, and he’s accomplished that and found himself in a pit of despair,” says Fox. “So I’m looking forward to that crawl out of the pit and finding some redemption in him.”

Of this season’s finale, his voice drops an octave into his Racer X baritone when he teasingly brags, “It’s got a really, really cool ending.”

A man of many secrets

With the ongoing enigma of “Lost,” his twist-centric role in last spring’s terrorism thriller “Vantage Point” and now the shadowy figure of Racer X (Is he or isn’t he Speed’s supposedly dead brother Rex?), Fox may have become the go-to guy to trust with secretive projects and characters.

“I don’t know what that says about me,” he says. “But I’m in a good place right now. I like things that challenge, and I think what’s fun for me about having lots of opportunities is not getting to where people say, ‘I know exactly what to expect from that guy.’ ”