PASADENA, Calif. -- Jennifer Love Hewitt will be starring in the new Fox series "Time of Your Life" this fall, a show built around her. Not bad for a 20-year-old.

But it's also a bit of a gamble. She's giving up a co-starring role on the established hit "Party of Five" to do it."I won't lie. Leaving 'Party of Five' is hard," Hewitt said. "It's incredibly exciting because this show is goig to be great. But I've said wonderful things about the cast of 'Party of Five' because they are incredible.

"They are a family for me. And Scott (Wolf) and I have worked together for a really, really long time and it will be very different not to see him every day."

The premise for the new show has Hewitt's character, Sarah, leaving Bailey (Wolf), her longtime boyfriend, and the rest of the Salinger family behind to go to New York City to search for her biological father. She eventually decides to stay there, her life becoming interwoven with a new group of twentysomething friends.

"It's hard playing Sarah being torn apart from Bailey, just because, you know, Bailey's Bailey. But it's good," Hewitt said. "I like seeing Sarah move on in her life and grow up and become who she's going to be."

And there are parallels between the move Sarah is making and the one Hewitt is making.

"I think, very much like Sarah's doing, when you grow up sometimes it means moving on and it means doing things that are hard at the time," Hewitt said. "But it makes you a better person and it teaches you something new, so I guess I'm sort of learning from my character in that way. And I'm moving from something that's really comfortable to something that's not so comfortable and going to see where it takes me. And, hopefully, I'll grow up in the process."

She admits she's a "little nervous" about the new show, which is only natural. But she won't be operating in completely unknown arena -- she is, after all, playing the same character and the show was created and will be executive produced by Christopher Keyser and Amy Lippman, the team behind "Party of Five."

"Mostly I'm really excited and always ready to work with Chris and Amy. The reason I wanted to do this show is because I don't ever want to not work with these people," Hewitt said. "They're amazing and they've made five years of my life absolutely incredible, and I've gotten to do the best work that people get to do and the chance to do it again in something new and even more fun was a great opportunity for me."

And not just in the acting arena. In addition to starring in "Time of Your Life," Hewitt is also a producer on the program. Not that she's exactly sure what that means just yet.

"They've been really, really wonderful about letting me be as much of a producer as I can be," Hewitt said. "I mean, I'll be very honest with you. I'm learning how to be a producer. It's something I really, really want to do. And it's not something that I just go and do very easily. I'm sort of learning and these are two great people to learn it from."

At this point, that producer credit appears to mean that Hewitt has at least some input into the direction of the series.

"I get to help decide where my character's going to go because I've spent a long time with her and I love her very, very much," she said. "And they keep me involved in all of those conversations. I get to sort of speak my mind on where I think the show should go and other characters should go and how they're going to grow. That's about it so far. But the show's pretty brand-new, so we'll see."

A lot of actors talk about the characters they play as if they're real people, separate from themselves, but Hewitt takes that to a new level.

"I've played her for a really, really long time and I feel really close to her. . . . I think Sarah is one of the most amazing people that I've ever come in contact with in my lifetime. I mean, she's not real, but at the same time . . .," she said. "She has been my role model growing up. And I think my biggest hope for her is that she grows up knowing that she is an amazing person. And my biggest hope for her is that she understands that being Sarah without Bailey is OK. I think it's really important for young women to understand that just being on your own and making mistakes and not having everything happen great all the time . . . is OK."

She loves Sarah enough so that she's signed away the next five years of her life (ratings willing) to continue to play the character on "Time of Your Life." And that move was at least a bit surprising for an actress who does seem to have a bit of a movie career going, with roles in movies like "Can't Hardly Wait," "I Know What You Did Last Summer" and its sequel and the upcoming Ben Stiller comedy "The Suburbans." But she doesn't worry about losing big-screen roles because she's committed to a TV series.

"I've never really worried about bigger plans," Hewitt said. "I like working and I like doing stuff that I believe in. And I believe in this. There may be movies that I may miss out on or things like that, but my heart is in this. So that tells me that this is what I should be doing.