A raw, personal journey.

That’s how a very high level production insider describes "Britney and Kevin: Chaotic," (search) the new six-part UPN (search) reality series based on home videos shot by Britney Spears and her new husband, singer/dancer Kevin Federline (search).

It debuts Tuesday at 9 p.m. EDT.

Says the insider, "She lives in a world where everybody thinks they know her, but they don’t."

The series, still in production, chronicles the courtship, engagement and wedding of the paparazzi magnets during and after Spears’ 2004 Onyx Hotel Tour (search). Spears and Federline are the executive producers.

The most surprising scene so far? "She shoots [all the tape] in the beginning," says the insider. "But as their relationship evolves and Kevin gains a foothold, he starts to shoot. There is a point where she is in denial about where the relationship is heading. She’s thinking that the whole thing is a set-up — that it was just a friend trying to put them together in L.A. before they left (to go on tour). But the reality is she’s just trying to put up another wall. And he stops her. He says to her: ‘You want to believe this is a setup because you don’t want me breaking down these walls. You’re really scared to love me. And that makes me really scared to love you.’

And it was such a powerful moment. She totally goes into denial: that push, pull, push, pull of a relationship. She’s scared. She says things like, "I didn’t mean it when I said I loved you. That was just me, playing around.’ And he doesn’t let her get away with it."

It should be noted that Federline has had two children — a newborn and a 2-year-old — with his former girlfriend, Shar Jackson; Spears had good reason to want to protect herself.

According to the insider, "There is no direct questioning" about the subject on tape. But she believes viewers will come away from this series liking Federline.

"He is soulful and direct. He’s got these amazing moments where he just cuts like a razor through the walls and the fears."