The Bones season 11 finale featured a shocking return from the show's early days.

***Spoilers through the season 11 finale of Bones below***

The Bones season finale that aired Thursday night concluded with a surprising cliffhanger. Zack Addy (Eric Millegan), a former Jeffersonian team member, was revealed to be Brennan's (Emily Deschanel) kidnapper! Zack was last seen being locked away at McKinley Psychiatric Hospital in season 3, having been in cahoots with the Gormogon serial killer.

As for what's next for Zack and Brennan, very few people know. Millegan spoke about his character's return in a new interview with TVGuide.com.

"The last time we saw Zack in real time was 8 years ago. There's a big hole with what's going on with him. He respects her. He is innocent of murder. He does feel that he was the accomplice to a serial killer so he feels like he would go to jail if people found out what he did," Millegan explained. "He wants to stay at the mental hospital where he feels he would do better. He is not crazy. Sweets [John Francis Daley] knew he wasn't crazy. Now, we have to deal with the fact that two years ago Sweets was murdered so nobody knows that Zack didn't kill anyone. In episode 1 of Season 12, everyone is going to find out exactly what Zack has been up to. It's a big episode. You find out everything."

Millegan also talked about how he might have some unfinished business with the rest of the Jeffersonian team.

"He cares about people," Millegan said, of his character. "He had a close relationship with Hodgins [T.J. Thyne], with Brennan and even with Angela [Michaela Conlin] and Cam [Tamara Taylor]. He had his own special relationship with Booth, which is explored in [the Season 12 premiere]."

Bones returns for its final season in 2017 on Fox, though the specific premiere date is not yet known. The final season was pushed back from its original fall 2016 premiere date.

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