Jamie Lynn Spears Engaged!

Access Hollywood
Jamie Watson and Jamie Lynn Spears - March 2, 2013 -- Instagram

Britney Spears and Jason Trawick may have called off their wedding, but there's another Spears sister getting hitched!

Brit's 21-year-old sister, Jamie Lynn Spears, is engaged to boyfriend Jamie Watson, 30.

PLAY IT NOW: Access Archives: Jamie Lynn Spears (2002)

The former Nickelodeon star announced the happy news via Instagram on Saturday.

"Guesssss what??????" she captioned a photo of her now-fiance and herself holding up her left hand to reveal her new sparkler.

VIEW THE PHOTOS: Stars Who Wed In 2012

She later added a close-up shot of her beautiful diamond ring with the caption, "He did good."

PHOTO: See Jamie Lynn Spears' engagement ring!

This will be the first marriage for the former "Zoey 101" actress.

VIEW THE PHOTOS: Celebrity Engagement Rings — The Bling Is The Thing!

Jamie Lynn has a 4-year-old daughter, Maddie, from her previous relationship with Casey Aldridge, whom she split from in 2010.

-- Erin O'Sullivan

VIEW THE PHOTOS: Jamie Lynn Spears

Copyright 2013 by NBC Universal, Inc. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.