Jamie Lynn Spears is Engaged!

When one door closes, another door opens. When one Spears lady gets dumped, another gets engaged.

Relatively hot off the heels of Britney Spears' split from fiancee Jason Trawick, her little sister and one-time teen mom Jamie Lynn Spears is showing off her new rock!

The 21-year-old budding country singer and mother to four-year-old Maddie broke the news on Twitter.

Jamie Lynn's new fiancee is, somewhat oddly, also named Jamie -- like her and her dad. His name is Jamie Watson, he's 30, and he has fantastic taste in jewelry, as evidenced by Spears' followup tweet, which featured a closeup of her round cut diamond.

This will be the first marriage for both Spears and Watson. Spears was previously engaged to Casey Aldridge, who fathered Maddie, but they split in 2010 before ever making it down the aisle.

Don't expect any jealous, catty behavior from big sis Brit, though. We hear the elder Spears has a delightfully normal new man -- and since she's got a Vegas residency coming up, we expect one bangin' bachelorette party!

Watch Jamie Lynn Spears Perform 'I Look Up to You'