It Happened One Christmas is a 1977 made-for-TV movie. It is a remake of the classic film It's a Wonderful Life, notable for the role reversal and surname change of the two main characters. Marlo Thomas stars as Mary Bailey, who, in contrast to the original film, is the main character rather than husband George Hatch, played here by Wayne Rogers. In another departure from the original film, the male angel Clarence Oddbody is now a female one named Clara Oddbody, played by Cloris Leachman. The part of the villainous Mr. Potter was played by film legend Orson Welles.
The film is mentioned a couple of times on Mystery Science Theater 3000. In one Christmas-themed episode, the Bots are disappointed when Joel promises to show It's a Wonderful Life and other Christmas films, only to reveal that they are all non-classic remake versions like this one, where Marlo Thomas is mentioned by name.
In another episode, Joel cites the tendency of Wayne Rogers, who played George in the film, to be the substitute whenever a TV remake of a movie occurs, including replacing Elliot Gould in M*A*S*H, Walter Matthau in House Calls, and Donna Reed in this one, the last of which confuses the Bots to no end, to which Joel then says that he'll explain another time.
The film was the final title under Daisy Productions, Marlo Thomas' own production company.