Third Time's the Charm: Britney Back in Rehab

Britney Spears is back in rehab. Again.

We're told the singer and everyone around her hopes the third time is a charm. The emergency custody hearing Kevin Federline wanted has been cancelled because of the new development. There will be no custody hearing today.

Sources say Federline is concerned for Britney Spears' welfare and wants her to get the help she is now seeking. But this will reportedly be the bald one's last chance - if she leaves rehab before getting full treatment, K-Fed plans to immediately go to court seeking orders allowing him custody.

TMZ sources claim Spears showed up at Federline's house last night and he wouldn't let her in. Those sources say the children are now in the custody of Federline and have been since last week.

Spears' inpatient rehab program is supposed to last between 30-45 days. It comes not a moment too soon. A source tells Us Weekly that his mother and Lynne Spears have joined forces to aid FedEx while he has cared for his sons.

"He is beyond sad," says a Federline pal. "This is the worst week of his entire life. He doesn't even want to pick up the phone. Things are beyond not well with Britney, and he wants her to get help. He still loves her."

Despite his estranged wife's wild ways, Federline reportedly is doing whatever it takes to care for little Jayden James and Sean Preston.

"Britney's family feels Kevin has been a blessing and they are very impressed with him taking so much responsibility," a Spears family source said yesterday.

"Britney's family found out from the news that Britney had left rehab again. She hasn't asked to see the kids because she knows she is not well and she does not want to scare [Sean Preston]. She has no credit cards or cash. She is basically on the run at the moment."