A.J. Cook A.J. Cook

A.J. Cook will return briefly for the upcoming season of Criminal Minds, while her co-star, Paget Brewster, has inked a deal to appear in most of Season 6's episodes.

Criminal Minds cuts A.J. Cook, will add new cast member, source says

"I'll be doing 2eps to wrap up JJ," Cook tweeted Friday. "Excited for what's next and hope you'll come along! XO."

Brewster will be around for much longer. The 41-year-old actress will appear in at least 10 of the 13 episodes this fall, and she is likely to appear in several more during the back half of the season, a source told TVGuide.com.

Criminal Minds' A.J. Cook thanks fans as online petition launches

In her tweet, Cook again thanked the thousands of fans who signed a petition in hopes of keeping her character, Agent Jennifer "J.J." Jareau, on the show. "Thanks for your undying support but it's a done deal," she wrote.

The 31-year-old actress was dropped from the show for "creative reasons," a source told TVGuide.com last week. She will be replaced with a new actress in the sixth season.