Britney Spears was "suicidal" last weekend following her custody battle over her two children, according to pals.

The troubled singer was so distraught over her struggle with ex-husband K-Fed she rang the Befrienders hotline to get help.

A source tells the News Of The World, "She's crying all the time. It's not the first time she's been suicidal."

The pal reveals Britney is so messed up she wants to get back with Federline.

"She wants him back. She thinks by getting Kevin back he'll drop the custody battle - but that's not going to happen," they explain.

However, Britney has reportedly come up with a B plan, if that doesn't work - fleeing to Cuba.

The source reveals, "She's terrified of losing her sons. There are no extradition laws in Cuba, so she thinks it's her only hope."