Joseph Gordon-Levitt in DETAILS

Maybe the only other actor generating as much heat as DiCaprio and Cotillard in the cast of Inception is Joseph Gordon-Levitt, who’s this month’s cover boy in DETAILS.

An extraordinarily bright kid, true: Get Joe rolling and it’s only a matter of minutes before the conversation is ping-ponging between Buddhism and Fellini, French poets and Russian clowns. But his brightness is so shiny and childlike, as he swivels around in an ergonomic chair at his house in the Los Angeles hipster playground of Silver Lake, that even his eyelids seem to grin. Start him talking about his new movie, Inception, the mystery-shrouded summer thriller directed by Christopher Nolan, the auteur behind The Dark Knight and Memento, and the 29-year-old actor appears to hover in a Tasmanian Devil funnel of static electricity. “He never loses his sense of enthusiasm‚Äîtruly boyish enthusiasm for the fun thing we’re doing,” Nolan says. “When you work on big movies, everybody gets jaded, myself included, and you have to remind yourself: If we were 10 years old, this would be pretty damn exciting. Joe never seems to forget that.”

When Christopher Nolan and his stunt director approached Joe about the role in Inception, they told him it would hurt. “I wanted to paint a grim picture of it,” Nolan says. “The worse I made it sound, the more Joe would grin.” There would be pain. There would be wire work‚Äîjumping and fighting in a Fred Astaire-ishly spinning room. Joe would need to wear elbow pads, knee pads, torso pads. Avoiding injury would require relentless training. “They were basically saying, ‘This will be really hard,’ ” Joe recalls. “And I said, ‘I will do anything at all, and I will never complain once.’ Chris just sort of smiled and said, ‘Get it in writing.'”

Nolan wasn’t lying. Joe went to England to shoot levitational hand-to-hand combat in a whirling tube set up in an old zeppelin factory, and “it was six-day weeks of just, like, coming home at night fuckin’ battered. Like you are after you play a hard game of football,” Joe says. “The light fixtures on the ceiling are coming around on the floor, and you have to choose the right time to cross through them, and if you don’t, you’re going to fall.” Nevertheless, there is no record of Joe bitching on the set. “The adrenaline,” he says, “was so nuts that I was like, ‘This normally would have hurt a lot, but let’s go again, let’s go, let’s go, let’s go.'”