McKinnon’s role and the film’s plot are being kept secret, though Gerwig is expected to put a new spin on the classic Mattel toy character given her previous work on “Lady Bird” and “Little Women.” McKinnon will star alongside Margot Robbie and Ryan Gosling, who will play Barbie and Ken. McKinnon and Robbie previously starred together in the Fox News drama “Bombshell,” playing fictionalized Fox News staffers who try to navigate life at the cable news network while founder Roger Ailes is accused of sexual harassment.