Which comes first--the actors or the scripts? In Fox's "Undeclared," it's been a mixture of both.

"We sort of do it backwards," said executive producer-creator Judd Apatow. Once he had the idea for a comedy series about college students, Apatow found the actors he wanted, listened to their experiences and watched their interactions, then shaped the characters and their stories.

"When we were cast, Judd called each of the actors," said Carla Gallo, who plays Lizzie Exley, one of the seven main college students in the show. "He asked me what I was like in college, as a freshman. As I talked, I could hear him typing. He created the characters around what we told him."

"Undeclared" has benefited from this approach, Apatow said. The show often starts with a script but, while shooting a story, the actors are told to wing it.

"We let the kids improvise a lot, to play with dialogue. It's the only way to catch those special moments -- we're just allowing room for something truthful to happen. Sometimes truth doesn't come out when a writer is at a computer at two in the morning, but when an actor reveals a part of himself."

"Undeclared," which premiered in September, airs at 8:30 p.m. on Tuesdays on Fox and is scheduled to present its last new shows of the season this week and next.

Apatow, 34, ("The Ben Stiller Show" and "The Larry Sanders Show") said one of the main reasons "Undeclared" was created was to keep together some of the team from "Freaks and Geeks," which he had produced.

When "Freaks" ended after 18 episodes in 1999, Apatow said, he was looking for an idea that would allow him to continue to work with "young, energetic, pleasant actors5/8I like to work with kids before they get powerful and turn on me," he joked.

"Undeclared" has been a reunion of many of the people from "Freaks," he said, including Seth Rogen (Ken in "Freaks"), who is a writer for "Undeclared" as well as playing the role of Ron, and Jason Segel (Nick in "Freaks"), who plays Lizzie's ex-boyfriend, Eric. "And the majority of the crew is the same," Apatow said.

"Undeclared" is about college life as seen through the eyes of Steven Karp, who hasn't yet decided on a major, so is undeclared.

Steven is played by Jay Baruchel, a 19-year-old actor from Montreal who said the show is about "dealing with this weird kind of responsibility for the first time in your life. Steven, who was a nerd in high school, sees college as a clean slate where he can start over -- but that persona lasts about a day. "

Baruchel, who has been too busy acting -- including a role in "Almost Famous" -- to attend college, said, "Steven is a thinly veiled version of myself. He's an exaggeration of my geekier, more awkward tendencies. "

Apatow sees a bit of himself in the characters as well. "At first I didn't think that 'Undeclared' was personal at all," Apatow said. "But after we shot the first 13 episodes, when I had some down time, I realized it was unbelievably personal. I had a long-distance relationship with my high school girlfriend

-- so I am both Lizzie and her psychotic ex-boyfriend. Any awkward character on that show is inspired by my past. I certainly am not [the character] Lloyd. That's where I use my imagination."

Steven's suitemates include Lloyd, a suave theater major from Britain, played by Charlie Hunnam; business major Ron, portrayed by Rogen; and music major Marshall, acted by Timm Sharp.

The four freshmen live across the hall from Lizzie, a psychology student; art major Rachel (Monica Keena); and Tina (Christina Payano), also undeclared.

The show, which has no laugh track, has covered topics such as pulling all-nighters, getting credit cards, fraternity rush, getting a job, dating and sex. Comic Will Ferrell made a guest appearance as an eccentric who writes and sells term papers to students, and Adam Sandler played a celebrity giving a concert at the fictional University of North Eastern California, then mingling with the students.

"The base of the show is relationships," said Gallo ("Spanking the Monkey"), 26. Her character, Lizzie, is struggling in her relationships with her long-distance boyfriend and with Steven, as well as learning to live and get along with her roommates. "It's about fitting in or not fitting in," she said.

Social patterns for the cast in real life were much like what happens in the dorm, she said. At first, the cast was put together, bonded, "and we were really tight -- we went bowling and did all sorts of things together. Then it let up and we didn't hang out as much -- much like what happens on frosh floors." Now most of the group gets together on Tuesdays to watch the show.

However, "the whole academic life of college doesn't seem to be taking up much of the lives of these people," said Roger Casey, dean of the faculty of Rollins College, whose specialty is popular culture. "Most of what college students do is go to class and do papers. But that's not entertaining."

Robert Thompson, professor of television and popular culture at Syracuse University, said, "'Undeclared' has used the dormitory as the place for human comedy. It's one place where television can show college and really work. There are all kinds of conflict and romance, with diverse people jammed in one place. It's the equivalent of 'Love Boat' or 'Fantasy Island' or 'Gilligan's Island' in that there are all these types of people in one place from which they can't escape. . . .

"College education and television probably is not a very good match. But a college dormitory and television is a match made in heaven," he said.

"The students haven't spent a lot of time in the classroom, mainly because they are getting to know each other and that's hard to show in a classroom setting," Apatow said. "As the series goes on, it would be more about choices they make in school, with Steven experimenting with different majors."

"Undeclared" ranked 88th of 172 shows this season, with an estimated average of 7.5 million viewers, according to Nielsen Media Research.

Whether the series will be continued next year is undecided, said Gail Berman, president of entertainment for Fox.

"If it does continue," said Apatow, "I guess at some time we would have to have Steven declare."

Loudon Wainwright: 'Undeclared' Dad

The main story line of "Undeclared" is about the lives of seven freshmen at college as seen through the eyes of Steven Karp, but there's another ongoing story about Steven's father, Hal, played by singer-songwriter-actor Loudon Wainwright.

"As Steven is starting his new life at college and all that goes with that, Hal also is starting his new life as a recently separated dad," Wainwright said. "It's sort of an embarrassment for Steven as his dad shows up in various situations, but his friends find him quite lovable because he's not their father."

Wainwright said he was asked to audition for the part because writer-producer Judd Apatow was a fan of Wainwright and his songs.

Wainwright, 55, released his first album in 1970 and in 1972 wrote and recorded the novelty classic "Dead Skunk in the Middle of the Road."

He also has written topical songs for National Public Radio's "Morning Edition" and sang in a guest-starring role in three episodes of "M*A*S*H."

Wainwright "has his whole other life" of performing in concert, said Carla Gallo, who plays "Undeclared's" Lizzie. "I've gone to see him perform twice and almost have become a groupie."