Director Robert Zemeckis said that, initially, a sequel was not planned for the first film, but its huge box office success led to the conception of a second installment. He later agreed to do a sequel, but only if Michael J. Fox and Christopher Lloyd returned as well. With Fox and Lloyd confirmed, Zemeckis met with screenwriting partner Bob Gale to create a story for the sequel. Zemeckis and Gale would later regret that they ended the first one with Jennifer in the car with Marty and Doc Brown, because it required them to come up with a story that fit her in, rather than a whole new adventure.