Britney Spears' hospital release has K-Fed "freaked out"

Kevin Federline is reportedly "freaked" out over Britney Spears' hospital release - despite winning custody of his and Spears' two sons, Sean Preston, 2, and Jayden James, 1, on Friday.

According to reports, the ex-husband of the troubled Toxic singer is furious over Britney's surprise release from Los Angeles' Cedars-Sinai hospital, after only 36 hours of psychiatric evaluation. And, a source close to K-Fed told America's OK! magazine that it has prompted K-Fed to beef up security at his Tarzana home.

Kevin is so worried that Britney will rush to his house and try to grab the boys, just like she tried to do last February," explains the source, who also revealed that 29-year-old Federline has doubled security at his Tarzana, Calif., home.

"The boys are safe for now," the source added. "But Kevin feels Britney is clearly deranged, and there’s no telling what she’ll do. After all, this is a woman who two days ago barricaded herself in her bedroom with her youngest child for three hours!" Adds the insider, "You can’t get mentally well in a hospital after 36 hours."

The source recalled an encounter from Feb last year, following Spears' multiple failed trips to rehab and her public head shaving: “She was so scared of losing custody of the boys that she drove to Kevin’s house three times and tried to wrestle her way inside to get her sons," the source added. "When Kevin refused each time, she took out her frustration on a photographer’s car by banging it up with her umbrella. There’s no evidence that Britney’s any saner than she was that day. In fact, she appears far worse."

Britney was carted off to Cedars-Sinai hospital late on Thursday after she reportedly refused to return Sean  and Jayden to Kevin.

She was pictured being stretchered out of the Beverly Hills home looking dazed and confused and carried into a waiting ambulance.

It has been claimed she downed a potentially deadly cocktail of vodka and prescription drugs shortly before the ambulance arrived. She has lost all visitation rights to the boys after the very public breakdown.