Hey, they were the original Olsen twins! Fraternal twins named Erin and Diane Murphy were cast to share the role of the Stephens’ daughter, Tabitha. It is quite common for twins to be used, particularly for the parts of babies. Babies have their own personality, so at any given time if one does not cooperate with filming the other can be used.
Both shows were about gorgeous blonde women with magical powers – Jeannie was a 2,000-year-old genie who falls in love with a NASA astronaut – and they both shared similar plot lines at times. But Elizabeth never felt any personal animosity toward I Dream Of Jeannie’s stars Barbara Eden or Larry Hagman.