Baby's momma to Britney Spears' husband, Kevin Federline, actress Shar Jackson has come forward and says she was "horrified" by the now infamous photos of Britney driving with her five-month-old son in her lap, rather than a car seat.

Shar goes on to say she "couldn't believe her eyes when she saw the pictures." A source revealed that Shar continued her rant exclaiming, "What was that [expletive] thinking? Is she crazy? What kind of mother is Britney?'"

As for Britney's insistence that the paparazzi made her do it, Shar isn't buying it. "[Shar's children with Kevin Federline,] Kori and Kaleb often stay with Britney and Kevin on weekends and after seeing those pictures, Shar's starting to worry whether Britney is responsible enough to be trusted to take care of her kids," reveals a source close to Shar.

"She's been trying to get Kevin on the phone and tell him he has to sit Britney down and tell her this should never happen again. If Shar doesn't get that kind of assurance, she's going to think twice before she ever allows Kori and Kaleb to stay with him and Britney again."

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