TMZ has learned Britney Spears will be leaving rehab this week, and she has made one of the most amazing turnarounds in celebrity memory. Sources say Britney and soon-to-be ex Kevin Federline had an “amazing meeting” on Sunday. They are not only getting along, they are hammering out the terms of custody. We’re told when Britney gets out, she and Kevin have agreed to a 50/50 split with physical custody of their two children. The plan is for Britney to eventually gain primary custody and Kevin will have visitation. Jamie Lynn, Britney’s sister, and Brit’s mom, Lynne, have been at Kevin’s house helping with the kids while Britney has been getting her own help in rehab. And that help is working. We’re told she has literally turned her life around. Stay tuned.