Britney Spears' younger sister Jamie Lynn has dumped the father of her baby, three months after reigniting their romance.

The former Zoey 101 actress, 19, fell pregnant with Casey Aldridge's child in 2007 and gave birth to daughter Maddie in June 2008. The couple announced plans to wed before calling off the engagement and splitting earlier this year, but was reported to have reunited in August after attending a Lady Gaga concert together.

However, Jamie Lynn Spears has ended her relationship with 21-year-old Aldridge once again, according to Star magazine.

A source tells the publication, "Jamie Lynn got fed up with Casey's immature behavior. She thought he'd changed - that's why she got back together with him. But he's still the same old guy."

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