For the third time in a week Britney Spears has checked back into rehab at the Promises clinic in Malibu. It is reported that Britney's ex-husband, Kevin Federline has issued her with an ultimatum asking her to get the full 30 day treatment or risk losing custody of the children.

In the wake of Britney's decision to check back into rehab, Kevin has agreed to cancel the emergency custody court hearing slated to take place today.

Britney's family is strongly rallying behind her and Extra TV reported that it was in fact Lynne Spears who drove her daughter back to rehab; Britney’s dad speaking to reporters said, " She is a sick little girl...we're just trying to take care of her and other than that I have no comment."