Topher Grace (Getty Images)

Topher Grace, a sometime romantic lead in sick-day favorites like Valentine’s Day and Win a Date With Tad Hamilton, plays the antagonist in The Giant Mechanical Man, his film that premiered last night at the Tribeca Film Festival. “There was a scene where I’m kissing Jenna [Fischer] and Chris [Messina] is watching and the camera closes in on Chris,” said Mr. Grace, “and I was like, ‘Oh, I’ve been in this scene, I’ve just never played this guy.’ Josh Duhamel or someone else is playing this guy.”

Mr. Grace plays a stringy-haired motivational speaker—shades of Tom Cruise in Magnolia!—who stands in the way of Ms. Fischer’s and Mr. Messina’s happiness. The actor became engrossed by late-night paid spots for speakers in the lead-up to his taking the role, though he was a bit dubious about their merits: “There’s a tone that all of them have to aggressively get you into something—and why would somebody want to tell someone else how to lead a better life? I’d never tell someone that, I barely have me figured out.” The character is a supporting role, not entering until past the twenty-minute mark, and Mr. Grace gets why: “One more minute of that character and you’d absolutely hate him. You’re supposed to love hating him and you might hate hating him.”

The actor, who’s currently acting Off-Broadway in the play Lonely, I’m Not, hadn’t acted live since high school, when a role in a school play led to him being scouted for his star-making role on That ‘70s Show alongside Ashton Kutcher and Mila Kunis. “I don’t feel any guilt,” said Mr. Grace of the more indie direction he’s been taking later, “although it’s not a good story when I tell my out-of-work actor friends, “I was in a high school play, then boom! 70’s!” Mr. Grace noted he’d been the age of Matthew Perry at the beginning of Friends when That 70’s Show ended. “There’s room for more, hopefully. My feeling was if you’re in something that’s been that moneymaking of an endeavor for everyone involved, then I never wanted to make a choice based on money ever again. And I haven’t.”

Topher! Not even Valentine’s Day? “I learned a lot of things on this,” he said, “and I learned a lot of things on Predators. I learned a lot of things on Valentine’s Day. If you’ve gotta do a romantic comedy, do it with Garry Marshall. This summer I did a film where De Niro and Diane Keaton are my parents, and one day they start talking about Godfather Part II, and I’m like “Okey-dokey! So worth it!”