How smart are you? Wanna prove it?

Audiences jumped at the chance last June when FOX aired "Test the Nation," a quiz previously staged on TV in other countries and encompassing all sorts of questions. The results suggested IQ levels according to gender, region, occupation and even hair color. Americans again can determine who is brainier, and why, when FOX televises the two-hour sequel "Test the Nation 2" Friday, March 5. Leeza Gibbons and Mark L. Walberg reunite as the hosts.

Also in the studio as celebrity test-takers will be Kim Coles ("Living Single"), Judge Mablean Ephraim ("Divorce Court"), Vincent Pastore ("The Sopranos"), Ben Stein and Fred Willard ("A Mighty Wind").

"I was surprised that people watched the show just as a program, not to take the test," Gibbons says of the first edition. "After each quarter-hour, we'd think, 'We're going to lose everybody who's not playing along,' but we didn't. In fact, we gained viewers as we went along. People picked up the show when it was already in progress, so I think it makes sense to do it again. Fox has a sense of where the real juice in the show is.

"Look, it's entertainment with a bit of substance," she continues. "Everyone loves self-discovery, and we like to know where we stand. That's what all this reality stuff is about: Where do you stand with a girl? Where do you stand with what you'll do to your body? It's all part of this bottom-line society we're in."

Originally announced as the sole host of the first "Test the Nation," Gibbons was pleased to get late addition Walberg to play off, and she looks forward to teaming with him again. "He's such a pro. He's so smart, he makes this look effortless. He can talk to anybody, and he has no ego. There's a handful of people who have that sort of `plug-and-play' personality, and he's one of them. I knew that five minutes into our first production meeting. We'd love to find more things to work on together. I just think he's very refreshing."

After fronting other unscripted FOX shows, including "Temptation Island" and "Anything for Love," Walberg says the "Test the Nation" specials are "really in the vein of what I enjoy doing. I'm one of those nerds who love to do logic problems and things like that, and that is what this show is. I would be a viewer of this, which I can't say for all the shows I've done. Working with Leeza is a joy, and doing a live show (which "Test the Nation 2" will be in the Eastern half of the country) is even more fun than that."

Hosting "Test the Nation" also gives Walberg exposure that helps him avoid being confused with Mark Wahlberg, star of such movies as "The Italian Job" and "The Perfect Storm." Walberg says, "There's still some confusion, and it's sort of a joke and a nuisance at the same time. I probably took it more seriously earlier in my career. That's why I added my middle initial -- not to be pretentious, but just so people could make the differentiation more for his sake. Yeah, right! He's the big movie star and I'm the game-show host. Sometimes, though, I get a better table at a restaurant because of it."

Gibbons is married to actor Stephen Meadows ("V.I. Warshawski"), a member of the intelligence-honoring organization Mensa; he took the first "Test the Nation" quiz at home while the special was airing. She reports, "He told me that he did better than the highest score revealed on the show -- so I immediately dismissed it. I moved right along to, 'OK. Who's picking up the kids tomorrow?' Why would you ever tell anybody your IQ or your SAT score? Aren't those limiting things? I don't know that you ever get a date or a job with your IQ, but there's the self-satisfaction of knowing where you stand at that particular point in time."

"Entertainment Tonight" and "Extra" alumna Gibbons soon will be a regular TV presence again: In June, she will become the host of "What Would You Do?," the unscripted Lifetime series that recommends ways to handle emergency situations. "It's the perfect fit for me," Gibbons says. "It's an empowering show, it's an informational show, and it honors and respects women's ability to make choices. We have great things in mind for it."

Gibbons also would be happy to do more "Test the Nation" specials if FOX decide to order them. "I love the energy you get from an audience," she says, "and I underestimated how much I would miss that part of my career. The challenge is to find the center of the seesaw, and this is just another tool to help me do that while reflecting the kind of programs I think I should be doing."