Britney Spears is finally in rehab. "Britney Spears has voluntarily checked herself into an undisclosed rehab facility today," her rep said in a statement. "We ask that the media respect her privacy as well as those of her family and friends at this time." Spears is at an in-patient facility in LA, reportedly at the urging of family members. The popstar's out-of-control behavior of late has raised the concern of her estranged husband Kevin Federline, who canceled plans to attend NBA All-Star festivities in Vegas over the weekend so he could be available for Spears and the two children they share. "Kevin is concerned for Britney and his children," says a friend of KFed. "Of course he's concerned about her. He loves her. He's always loved her - even after she started divorce proceedings." Though the name of Spears's treatment center has not been publicly released, she has reportedly been seen smoking cigarettes on the grounds of Promises Treatment Center in Malibu.