Is Shar Jackson Looking After Britney's Kids?

Was the real reason Britney wasn?t allowed entry into chez K Fed before her third rehab attempt because his other ex Shar Jackson was there?

That?s what both the National Enquirer and Star Magazine are reporting. They say Miss Jackson was helping Kevin look after Britney?s two children ? Sean Preston and Jayden James, and if Britney found out she would be mortified as she?s said to be jealous of Federline?s original ?baby momma?

They also claim Shar wants to get back with the wannabe rapper - so maybe Britney was right to be jealous?

However, as we previously reported, Kevin has said he still loves Britney and he wants to give their marriage another try once she successfully completes rehab.

The Enquirer also claims that Britney?s family have given her an ultimatum: if she doesn?t finish rehab and sobers up, they will commit her to a mental hospital!

?Britney doesn?t think she has a problem. She agrees to go into rehab only because Kevin promised they?d be back together with their babies if she finished the program,? revealed a source close to the couple, the Enquirer claims.

?Shar has been at Kevin?s house helping him with the boys? Britney is terrified Kevin will get back with Shar. If Britney finds out what?s going on, she?ll go ballistic. There?s no doubt she?ll bolt from Promises and go running to get the kids.?