And she's off!

Britney Spears has finished her "nearly one-month stint" in rehab and has left Promises rehab facility.

Spears "has been released by the Promises Malibu Treatment Center after successfully completing their program," rep Larry Rudolph said.

A friend says, "Her time in rehab has given Britney a lot of time to think, and has shown her Kevin loves his kids and is a good dad. She is doing fine." You know it's minutes before the crazy starts back up...