They say the camera adds 10 lbs. On the set of Heroes, “we use three cameras, so that’s 30 lbs.,” jokes Greg Grunberg.

“I saw the [pilot] before it aired,” says Grunberg, “and I was really big!” How big he won’t say, but “I was barely squeezing into my 40″-waist jeans.”

His wife and mother each had had success with Weight Watchers and wanted Grunberg to try it.

With due respect to the women in his life, he says, “to me it was an old lady’s diet, a soccer mom diet.” And yet Grunberg was soon one of a few men attending meetings.

At home, Grunberg made changes: no processed foods (save for sugar-free popsicles) and no eating for four hours before bed. He now bikes 30 minutes a day and lifts weights every other.

Although he took some on-air ribbing from Conan O’Brien about counting points, Grunberg eagerly agreed when Weight Watchers asked him to be its first male celeb spokesperson.

Down two sizes and 33 lbs. (with 20 to go, he says), “he is standing prouder,” says wife Elizabeth. “There’s an extra spark of confidence,” adds costar Ali Larter.

And, says Grunberg, “my agent said if I lose 15 more pounds I can do more leading man roles.” One thing you won’t see him do? “I’m not,” he insists, “going on a talk show wearing a bikini.” [via]