Jamie Lynn Spears is engaged, People Magazine is reporting, after noticing the Zoey 101 star's sparkly new engagement ring from baby daddy Casey Aldridge. The source reports:

Mom-to-be Jamie Lynn Spears is sporting some sparkling new jewelry - an engagement ring from fiance Casey Aldridge.

Spears, 16, has been flashing the rock to friends and family around Louisiana and Mississippi, a source close to the family tells PEOPLE.

"She's got an engagement ring," the source says. "She's been showing it off, talking about it."

Hmm. So maybe the baby really isn't some tv producer's bastard fetus???

Britney's little sister, Jamie Lynn Spears, has a lot more in common with her popwreck older sister than we once hoped. The SIXTEEN year-old Nickelodeon "Zoey 101" actress is PREGNANT, and expecting a child most likely this summer.

The father is Jamie-Lynn's "long-time boyfriend" Casey Aldridge, but the stability of their relationship is doubtful.

In November, Jamie-Lynn told the Associated Press that she was single and did not have a serious boyfriend. "I kind of just keep my options open," she told them. "I have a bunch of friends that I always hang out with, a bunch of guy friends."

A month later - the boy has quickly been upgraded to "long-time" boyfriend - a change that probably has more to do with the Spears's Southern Baptist values and "devout Christian" beliefs (yes, believe it or not, those values are even buried inside Britney Spears...deep, deep, deep inside....somewhere in there...). Surprisingly though, there has been no talk of marriage, and lots of talk of splitting.

A Spears insider tells Life&Style that Casey and Jamie Lynn are on the rocks and are no longer dating one another:

"Jamie Lynn and Casey are NOT together. They've broken up numerous times, but he was her first and she kept taking him back. At this point, Jamie Lynn has asked her mom - and not Casey - to be in the delivery room with her."

But Jamie-Lynn's own words in her OK! Magazine interview suggest a more harmonious relationship to her babydaddy. While she acknowledges that the pregnancy was "a shock for both of us," Jamie Lynn explains that keeping the baby was a mutual decision:

"Casey was 100 percent supportive. He has always been good with babies. He's like a big teddy bear, especially around babies, so I know he'll make a good dad," she says, adding that Casey and Mama Lynne both attended her first ultrasound. As for marriage? "Right now, we're just focusing on the baby and having a healthy baby. We're trying just to think about that right now so we haven't really talked about that."

Not surprisingly, mama Lynne has decide to put her "parenting book" on hold. The "personal story of raising high-profile children while coming from a low-profile Louisiana community" is "delayed indefinitely," according to her publishers. Probably a good idea....Right now might not be the best time to brag. But at least Jamie-Lynn's pregnancy will give Mama Lynne even more dramz to write about!

Meanwhile, daddy Spears is said to be "furious and devastated", while Britney had NO clue about her sister's pregnancy...until she read it in the tabloids. In fact, K-Fed actually learned of the pregnancy before she did! Unlike Britney, who must have had yet another falling out with her mom and sister since their October reunion, Kevin keeps in touch with Lynne and Jamie Lynn regularly. And according to K-Fed, the estranged popstar was not expected to be happy about the news. "We're waiting for the fallout from Britney," an insider told Page Six. "Kevin is sure Britney will flip out and blame her mom and dad." Well, ya can't blame her for being unhappy with the news - if anyone knows firsthand why being a young mommy is bad news, it's Britney!