Moore will reprise his role as FBI agent Derek Morgan, guest starring in the season 12 finale airing Wednesday, May 10, where Morgan will bring the BAU a lead in the case against serial killer and escaped convict Mr. Scratch, who has wreaked havoc on the team all season.
"BOOM," Moore wrote on Instagram. "My secret is out !!!! I'm excited to say.... Your Baby Boy will be back to play with my Criminal Minds family for the season 12 Finale!!"
Moore was a series regular on Criminal Minds from its inception in 2005 through 2016, when he left in the middle of the 11th season.
“I’m not leaving to go be a big star and try to make a lot of money,” Moore said at the time. “I mean, all that stuff is part of the business and part of the journey and the dream, [but] right now I’m just leaving to take a breath.”
Moore promised that his final episode “was not goodbye.”
“Derek didn’t die, so anything is possible,” he hinted, adding, "When I come back, I'm going to come back guns blazing and excited and ready to perform and dance and, hopefully, the fans will enjoy what I'm doing."
Criminal Minds has seen a few cast changes over the course of the 12th season, with series regular Thomas Gibsonabruptly exiting after a reported on-set altercation, the return of Paget Brewsterand the addition of new regularDamon Gupton.
Criminal Minds airs Wednesdays at 9 p.m. ET/PT on CBS.