"Prisoner" Britney says marrying K-Fed wasn't the best idea

"I think I married for the wrong reasons," she said of her marriage to the baggy pants aficionado.

"Instead of following my heart and doing something that made me really happy, I just did it for the idea of [marriage and] everything."

The 'Womanizer' singer, who drops new album Circus this year, says in the documentary that her popstar life isn't one to be envied.

"There’s no excitement, there’s no passion," she moans. "I have really good days, and then I have bad days.

"Even when you go to jail, y'know, there’s the time when you’re gonna get out. But in this situation, it’s never ending. It’s just like Groundhog Day every day."

Yep, she just compared her life to jail time. Apparently since her head-shaving, marble-losing days, he life is extremely regulated.

"I think it’s too in control," she says. "If I wasn’t under the restraints I’m under, I’d feel so liberated. When I tell them the way I feel, it’s like they hear but they’re really not listening. If you do something wrong in your work, you can move on, but I’m having to pay for a long time.

"I never wanted to become one of those prisoner people. I always wanted to feel free. I think I've learnt my lesson now and enough is enough."