From PEOPLE Magazine Click to enlarge
Even Sherlock Holmes can be stumped. Jonny Lee Miller, now starring as the famous detective on the hit drama Elementary, wasn't sure how to react when his son Buster, 3, asked why Dad's face was on a double-decker bus. "We explained that I made a grown-up show that he can't watch," says Miller of Buster, who is, at least right now, totally uninterested. "It's not his cup of tea. He likes to ride the subway and go to the playground!"

These days Buster may be the only one not fascinated by his father. Elementary's instant success has turned Miller, who rose to fame in 1996's Trainspotting, into fall's breakout star. Still, until CBS picked up the show for a full season, the actor, 39, remained "a cautious person" as he'd seen other projects fail to thrive. "Until something happens," he says, "it hasn't happened." Yet he's not quite so buttoned-up: Miller, who was married to Hackerscostar Angelina Jolie from 1996 to '99 ("It was a lifetime ago," he says, "but we are in touch") has been logging serious miles training for the Nov. 4 New York City marathon and experimenting in the kitchen at home ("I have my own recipe for Bolognese," he shares) for his wife, The Shield actress Michele Hicks, 41, and Buster. At this point "we don't have a plan," he says. "And so far, so good!"