LATEST: Troubled pop star Britney Spears got a boost in her recovery efforts when her young sons stopped by her treatment centre for an early morning visit on Wednesday (07MAR07). The TOXIC singer checked into Promises Residential Treatment Center on 21 February (07) to deal with her substance abuse issues. And estranged husband KEVIN FEDERLINE brought the couple's two children, Sean Preston, 17 months; and JAYDEN JAMES, six months; to visit their mother. Federline and his sons left his house in Tarzana, California in a black Lincoln Navigator Sports Utility Vehicle (SUV), outfitted with curtains to ensure privacy for the 6am rehab visit. A source tells American publication Us Weekly, "It seems like Britney is struggling being away from Sean P and Jayden because Kevin let her spend four hours with the kids." Federline and his mother, along with Spears' mother LYNNE, have all come together to care for the couple's children while Spears is recovering in rehab.