Marilyn Monroe named her chihuahua Josepha after geezerly Hollywood mogul Joseph Schenck, who in 1948 gave her the dog as a gift. She thought of Schenck as a mentor, but he thought they were dating. Soon she had taken to calling Josepha by the nickname Choochoo.
Here's a charming video of Marilyn interacting with a badly trained dog on the film set of her unfinished movie Something's Gotta Give (1962). The dog's name is Tippy, which oddly enough was the name of a dog she had in childhood. Though the dog in this footage is not a chihuahua, it is a delight in showing the authentic patience and affection she had for dogs: