Britney Spears has entered rehab for the third time in less than a week according to TMZ.com. The emergency custody hearing has been canceled due to her third attempt at curing her ills. Sources say Kevin Federline said he would cancel the hearing if she entered rehab again today.

Sources tell TMZ Federline is concerned for Spears’ welfare and wants her to get the help she is now seeking. We’re also told this will be Spears’ last chance — if she leaves rehab before getting full treatment, Federline will immediately go to court seeking orders allowing him unquestioned full custody of the children.

We’re told Spears showed up at Federline’s house to see the children last night and he wouldn’t let her in.

I can’t say I blame Kevin for playing hard ball at this point. It all makes his case for custody look that much stronger. Basically he is giving Britney rope to hang herself and she is doing a terrific job at it.

More stories on the ever-saddening story of Britney Spears

• Will 3rd time be charm for Britney and Rehab?
• K-Fed going for custody of his boys
• Britney Ditches Rehab (AGAIN)
• Britney Spears enters Rehab (again) this week
• Britney Spears totally ‘wiggin’ out
• Britney’s mop of hair being sold on Ebay
• Britney goes from Bald Eagle to Bald Head
• Worst Bald Head of the Day: Britney Spears
• Britney goes Bald YouTube Video
• Bloggers respond to Bald Brit Madness
• Britney Spears enters, leaves rehab in same day
• Britney Exposes her Bald Spot
• Oops! Britney does it again (this week)