For Underwood, best known for his seven seasons on TV's "L.A. Law," making this new film, "Full Frontal," was a view of the Hollywood elite stripped of all pretensions. Some of the movie was shot at Soderbergh's house. No one was allowed to bring assistants or hangers-on. No one got a trailer. And they had to drive their own cars to the set.

Much of the 18-day shoot was designed for improvisation. Underwood didn't even meet Roberts until five minutes before their first scene. (He plays an actor, and she plays a reporter interviewing him. Yes, sexual tension results.) "It was a way to get back to the basics of filmmaking," Underwood says. "All the leads were given digital cameras to take pictures behind the scenes for the Web site," fullfrontal.com.

Underwood, 37, has built a career at all levels of the entertainment food chain, from independent features like the upcoming "G" (he's the title character, a hip-hop mogul, in a retelling of "The Great Gatsby") to big-time TV projects like the Steven Bochco medical drama "City of Angels." That CBS show, with its mostly black cast, was seen as an answer to NAACP complaints about too few minorities on TV. It was among the highest-rated shows in black households, but overall ratings were only fair, and it was canceled last year after two seasons.

When he took the lead role, Underwood worried that if "Angels" failed, it could be a huge setback for black actors on TV. "The perception was, if someone of Steven Bochco's caliber couldn't make people watch a show with an African-American cast, who could?" He speaks carefully, saying he hopes TV moguls will consider the competition the show had (NBC's Friends, ABC's "Who Wants to Be a Millionaire") and won't use its demise as a reason to abandon diversity.

Frank Underwood, his older brother and longtime producing partner, is more blunt: He says network executives were thinking, " 'Black people are upset. Throw them a bone.' If the show worked, great. If not, they could say, 'We told you so.' " The actor was depressed when the show ended, but he shook it off. "That comes from our upbringing," his brother says. "Our dad taught us that when something bad happens, you get up and keep on stepping."

The Underwoods grew up as military brats, traveling from city to city with their father, an Army colonel. A star swimmer as a kid, Underwood spent a lot of time doing laps in the pool at the Pentagon when his dad was stationed there. His father raised him with a strong sense of patriotism, he says, "tempered with the reality of being an African American. I look at the country as a family, but a dysfunctional family."

On Sept. 11, Underwood felt great "anger at the audacity" of the attackers. He and his wife, Desiree, have two sons, 8 months and 5, and a daughter, 3, and that night, as he changed the baby's diaper, "I found myself apologizing that I would not be able to give him the world we had just the day before."

Underwood feels he is in "a different place" in his career, too. He lives near Brad Pitt in the Hollywood Hills, in "the house that 'L.A. Law' built." And although he appreciates the riches, "warm memories" and entree into Hollywood that series provided, he has opted not to appear in a reunion show planned for this spring. Doesn't he owe it to his fans to update his character, Jonathan Rollins? Underwood takes a deep breath. Fans, he says, "are going to cuss me out. I know that."

Still, this was a decision he and his agent made together, he explains, and he'll likely stick with it. He insists it has nothing to do with the perception that reunion shows are for has-beens, but he also says he'd like to move up in the ranks of sought-after actors. "You never know where you are in line" for movie roles, he says. "But you sure know if you're first in line."

Of course, having Roberts for a leading lady has to help as he queues up for more roles. "She was such a joy," he says, grinning. Even if "Full Frontal" isn't a hit, "the experience was the reward."