The Parent Trap 1961

One of a handful of family films Hayley Mills made for Disney when she was in her teens (they also include That Darn Cat!, In Search of the Castaways, Summer Magic and The Moon Spinners), this is the best loved and best remembered. She plays twins Sharon and Susan, one who is raised by their father and the other by their mother after their parents divorced. Neither knows the other exists until they meet at summer camp and conspire to swap places so that each girl can get to know the parent they have never met and hopefully reunite the two adults.
It’s sprightly stuff, with nice support from Keith and O’Hara as the parents (and a deliciously spiteful turn from Joanna Barnes as dad’s new girlfriend), but what is most impressive here are the special effects, ground-breaking at the time, that allow two Hayley Mills on screen at once (a body double, Susan Henning, was only used in some of the shots, the rest is camera trickery). Kids now, of course, won’t be impressed, but it adds to the fun of this cheery little film.