Guest star news flash: Francis Fisher will be guest starring in Criminal Minds.

The actress, best known for playing Jack Dawson's mother in Titanic and more recently for working on ABC' s Resurrection, will be guest starring in the penultimate episode, entitled 'Devil's Backbone' of Season 11.

Showrunner Erica Messer revealed the nature of Fisher's role to TVLine in the episode, which will be "very interesting" and "creepy"/"psychological". According to the report Fisher will be playing the part of Antonia Slade, "a crazy UnSub who was put away by [Mandy Patinkin's] Jason Gideon 15 years ago."

As for the character's backstory, Glade had been involved in a twisted case with her husband wherein they operated a teen runaway helpline, but were criminally harsh on toward the ones that did not comply or were deviant.

Messer expressed her delight at finally getting Glade to guest star in the CBS procedural.

"She's amazing," Messer said. "We've been wanting to work with Frances Fisher for years and it never worked out, and we're so glad it didn't, because she was made to be this UnSub for us."

In other news relating to guest stars on the show, the latest episode, entitled 'Tribute,' saw the return of Paget Brewster as Emily Prentiss. After Derek Morgan's (Shemar Moore) shocking exit, Prentiss might have offered brief respite to fans.

Previously speaking to TVLine, Messer also expressed her excitement at getting Brewster back on the show, and how her schedule freed up at the right time, with production for Grandfathered completed.

"I'm so excited that we get her finally," Messer said. "And the timing couldn't have been more perfect," given that longtime team member Derek Morgan just delivered a round of sad goodbyes after deciding to quit the FBI and be a family man. "We really wanted to do something big after Shemar [Moore] left," says the EP, "and there's nothing greater than bringing back our sweet Emily Prentiss."

'Devil's Backbone' will air on April 20.

The next episode, 'Inner Beauty,' will air on April 13.

Watch the preview for the latest episode, 'Tribute':