A.J. Cook is back at the BAU, if only for a week.

According to TV Line, the actress whose exit such enormous viewer backlash this fall will reprise her role as Jennifer “J.J.” Jareau for one episode this spring.

It’s unclear what prompts her return, when exactly her episode airs or whether she may return for more than just that week, but she's due on set this week.

A.J. Cook is headed back where many feel she never should've left.

J.J. bid farewell in the second episode of the current season to take a job at the Pentagon. The character seemed as reluctant to do so as millions of fans were to see her go.

When news broke that Cook’s contract was not being picked up by CBS, fans mounted a huge online campaign demanding the network save Cook and Paget Brewster.

Might J.J.’s comeback be tied in some way to the looming exit of Brewster's character? It's been speculated at length that Minds may kill off Prentiss later this spring.

CBS recently defended its casting moves, including the hiring of Rachel Nichols shortly after Cook's exit, maintaining that Brewster's future with the show is up to her.

Share your thoughts and theories on Cook's return below!

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.