'Criminal Minds': Rachel Leigh Cook Will Play Reid's New Love Interest in Season 15

Criminal Minds will make Spencer Reid's personal life even more complicated in its final season.

Two weeks after Season 14 ended with a shocking love confession from JJ (A.J.Cook) rocked Reid (Matthew Gray Gubler), the series announced a new face will be arriving as a possible love interest for the beloved member of the BAU.

Rachael Leigh Cook (Perception) has been cast in a recurring role for the 10-episode final season of Criminal Minds as Mac, a quirky, kind-hearted, candid woman who strikes up an unusual relationship with Spencer, as first reported by TVLine. The actress is set to appear in at least two episodes of the final season.

The arrival of this new woman in Reid's life will make his life a little more complicated, as JJ admitted to her colleague that she had strong feelings for him when they were both held at gunpoint during the Season 14 finale.

"Spence... I've always loved you," JJ shared during a deadly game of "Truth or Dare" with the Unsub. "I was just too scared to say it before. And things are really just too complicated to say it now... I'm sorry. But you should know."

Series executive producer Erica Messer previously teased that the confession will be a major plot point during the first episodes of the last season.

"It's definitely a huge driver for the first handful or episodes that will help add layers to those characters again," she told the outlet.

Fans shared mixed reactions to the finale cliffhanger, worrying about how JJ's confession could admit her marriage and family.

"Her confessing that doesn't mean she doesn't love the life she has tremendously," Messer told Entertainment Tonight. "Without giving away too much of the actual dialogue that's coming up, she's been defined by the love in her life and the love in her life is Will and the kids, it's Reid, it's her friends, it's the work that she does. There are a lot of things that define people and [Reid] is one of those things to her. Maybe if she had never met Will in season two, things would've been different. If in another time and place... There's heartbreak to that but you would want to know that in a friendship or relationship. It's complicated."

The Season 15 premiere will reportedly pick up six months after the events of the finale, and will see some "messy" consequences after so much time.

"We didn't want to play the 'will they-won't they' or 'she's got to make a choice.' It's a little bit messier than that," Messer added. "When we meet them in the first two episodes of season 15, what we learn is they haven't really talked about it because it's made that much of an impact. Six months have passed story-wise and it's time they talk about it. It gets muddy."

Criminal Minds will return for its final season during the 2019-2020 television season.