Castle season 8
Stana Katic teases major event that will "shift the entire season into a higher velocity", in Castle season 8ABC

Castle season 8 is a few months away from its premiere, but the shows lead actress Stana Katic has teased that the upcoming season will be full of shocking twists, including that of the mystery behind Rick's kidnapping and subsequent loss of memory that happened in season 7.

Katic referred to the two-part premiere episode as "brother and sister", which will feature "an event that shifts the entire season into a higher velocity", Deadline reported.

She also teased that the revelations will set the plot for the "next 20 episodes" of the super hit ABC crime thriller.

Season 8 will explore the cosmic relationship between the mystery novel writer and his detective wife, who got married in the previous season.

"The new season is the way new show runners Alexi Hawley and Terence Winter have envisioned the cosmic version of why the two characters have come together," Katic told the website and added, "It delves into the mythology of Rick's disappearance and memory loss as well as into what inspired Beckett to become a cop in the first place."

The filming for season 8 has already begun. Here are some set pictures from episode one.

Season 7 of Castle ended on a cliffhanger as Kate Beckett was offered a chance to run for the state Senate, but whether she accepted the proposal or not, was not really shown.

Castle season 8 will premiere on 21 September on ABC.