Steven Moffat, showrunner of the highly anticipated returning television series "Doctor Who," has teased the show's fans about the regeneration of Peter Capaldi and how it will lead to a new dynamic between the new Doctor and his companion Clara, describing it as "frightening," Digital Spy reports.

In the series opener of the eight season entitled "Deep Breath," Clara Oswald, who is portrayed by Jenna Coleman, is caught off-guard by the personality change of the Doctor as the two are on an investigation in Victorian London. TV Line was given previews to the upcoming episodes by Moffat, wherein he hinted that the new Doctor portrayed by Capaldi would be defying expectations from the first moment he goes on screen.

Additionally, Moffat pointed out that the unique approach used by Capaldi in portraying the Time Lord contributes to the different feel of the upcoming season and how his brave and bold disposition in finding his own path has made the changes.

Moffat gave the teasing preview by asking how it would be like being Matt Smith one moment and suddenly becoming Peter Capaldi the next moment, referring to the Doctor's transition. He gave his own answer to the question, saying, "It must be frightening," especially as the best friend who sees someone else while looking right through his eyes. This interesting event would very likely set the tone of the upcoming season, which fans have been counting down to.

Prior to the release of the upcoming season, Capaldi and Coleman have been going around the world for a promotional tour around five continents with stops in Brazil, New York, Australia, South Korea and London, where the two took part in question-and-answer sessions with Doctor Who's massive fanbase.

"Deep Breath" will be premiering on Aug. 23 on BBC One in the U.K. and on BBC America for the United States.