Written by Danny Chun and produced by Dan Fogelman, Grandpa centers on Jimmy (Stamos), a charismatic longtime bachelor whose life is upended when he discovers he’s a father — and a grandfather. Peck plays Gerald, the son Jimmy didn’t know he had – a sweet unemployed techie who is himself the proud and surprisingly capable father of a two-year-old daughter, the product of a one-night stand with the sexy Vanessa (Christina Milian).
Brewster plays Jimmy’s old girlfriend Sara, a former rocker chick who became pregnant with his child 26 years ago, but has raised their child, Gerald, single-handedly. She never made Jimmy aware of his son’s existence — but now, Gerald wants a strong father figure to teach him how to navigate the rocky shoals of romance, so Sara is forced to disrupt Jimmy’s long bachelorhood at long last. She’s seemingly contemptuous of his bachelor persona — but underneath, their old attraction may still be simmering on the back.
Brewster, repped by UTA, manager Joannie Burstein and attorney Joel McKuin, has been focused on comedy since ending her stint on dark CBS drama Criminal Minds with several pilots and guest shots as well as a season-long arc on the upcoming sixth season of Community.