'Castle' season 8 premiere spoilers: New characters to be introduced in 2-part season 1 premiere episode

Castle and Beckett might be parents in Castle season 8ABC

"Castle" season 8 will have an explosive two-part premiere special to introduce new characters that will be involved in the lives of Richard Castle (Nathan Fillion) and Kate Beckett (Stana Katic). 

TVLine exclusively revealed two new characters that the double-episode premiere will usher in. In the first part titled "XY," former Scotland Yard officer-turned-security specialist Hayley Vargas and tech analyst Vikram Singh will join the NYPD team.  

Vargas, portrayed by "The Neighbors" star Toks Olagundoye, is known as a free-spirited witty former police officer who is willing to cross lines to be able to get what she wants. Speculations claim that Vargas could be a threat to Castle and Beckett's relationship this season. 

Meanwhile, the edgy tech analyst Singh with a complicated past will be portrayed by "The Walking Dead's" Sunkrish Bala. 

For the second part of the season premiere, "Private Practice" alum Ann Cusack joins the series as Rita. The character is described as a member of highly-confidential organization who suddenly appeared in Beckett's life with a special set of skills. She also allegedly has an unexpected connection to Castle's life. 

In a recent interview with Deadline, Katic talked about the premiere episode of "Castle" season 8.

"Part of the exciting thing about this season is the way [showrunners] Alexi and Terence have envisioned the cosmic version of why the two characters (Castle and Beckett) have come together, how these roads combined," the actress said. "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." 

Aside from the entry of the new characters in "Castle" season 8, the series' latest showrunner Terence Paul Winter announced that fallen senator William Bracken will return "in a surprising way." Bracken was the instigator of the murder of Beckett's mother Johanna. Jack Coleman will return to the series as the ruthless senator when the series returns this fall.

"Castle" season 8 premieres on Monday, Sept. 21, on ABC.