Cover Story: Britney Trades Kids for Fame

But it's no secret that, as she starts to climb back to the top, there are sacrifices she's had to make along the way — specifically, spending less time with her two adorable sons, Sean Preston, 3, and Jayden James, 2.

Now, OK! has learned exclusivly the extraordinary price the singer is paying for her comeback, voluntarily giving up the fight to regain custody of her boys in exchange for fame.

Last fall, as her upcoming concert tour was being organized, Brit's camp discovered that because of the star's history, they could not purchase insurance to cover her tour unless she was still under the conservatorship of her father Jamie Spears. Until that point, the plan was for the conservatorship to be lifted on Dec. 31, followed by Britney, 27, heading to family court with a petition to regain custody of Preston and Jayden.

But an insider tells OK!, "The insurance situation changed everything."

And so, on Oct. 28, the singer agreed to indefinitely accept her father as her conservator – a decision which meant she would still legally be considered a child. No judge would give her custody of her kids, nor would her ex-husband, Kevin Federline, agree to it.

"Whether it was her decision or whether she was pressured into it, Britney's deal with the devil put the tour ahead of the kids," the insider tells OK!.