There will be noticeable changes to "Criminal Minds" when the long running CBS series returns in the fall.

For one, executive producer Erica Messer confirmed Jennifer Love Hewitt will not reprise her role as Kate since she is pregnant in real life and plans to take time off for maternity leave.

However, series star AJ Cook also revealed that she, too, is pregnant during the Season 10 finale. As a result, Messer revealed that her character, JJ, won't be featured in the first couple of episodes of the new season since Cook will be on leave. Instead, the show will find a way to write around her maternity leave while she is gone.

Speaking to Entertainment Weekly, the showrunner explained that the season finale "helps us answer why she's likely not in the first episode or so."

"We laid the groundwork for it, and then we can remind everybody in the premiere that she's on maternity leave," she continued.

During an interview with TV Guide, the executive producer said that rather than introducing a new character to replace Kate, Messer said they are toying with the idea of bringing back familiar faces to guest star or continuing the "revolving door" of new agents. She is also open to the idea of bringing Hewitt back for a potential Season 12.

"We like people to come back and play whenever they can, so we don't kill them off," she said, adding that Hewitt's departure was "organic and surprising in a good way."

She continued, "None of us thought at the beginning of the season we'd end the year with two pregnant actresses! And right now, it's too soon to say what would happen in two years if we're lucky enough to have [a Season 12]. We would love to have her back."