Britney Spears' estranged husband Kevin Federline is desperately trying to convince the pop star to check into rehab, according to media reports in the US. Since filing for divorce in November (06), the TOXIC star has been out on the town almost every night and Federline is concerned about her well-being. A source tells American publication Star, "He's afraid she's going to hurt herself. Kevin has tried to convince Britney to check herself into rehab from every possible angle. "First he tried threatening to take away the kids, then he tried pleading with her to take care of herself." Federline even reportedly enlisted the help of Spears' mother, LYNNE, in an effort to convince the singer to get help, and fears Spears isn't spending enough time with their young sons SEAN and JAYDEN. The insider adds, "They're being raised by strangers. He told Britney to get help before it's too late."