All of Me is a 1984 fantasy comedy film directed by Carl Reiner and starring Steve Martin and Lily Tomlin. This film is based on the novel Me Two by Edwin Davis.
Dissatisfied 38-year-old attorney Roger Cobb (Martin) is dating his boss' daughter and is also an aspiring jazz guitarist. A difficult, eccentric millionairess named Edwina Cutwater (Tomlin) has been bedridden since childhood. Cutwater hires Roger to make some unusual final arrangements to her will.
Having discovered she is dying, Edwina has enlisted the aid of a culture-shocked mystic named Prahka Lasa (Richard Libertini), who has mastered the secret of transferring human souls. She has made an arrangement with Terry Hoskins (Victoria Tennant), a beautiful young woman. Edwina wants her own soul placed in Terry's vacated body so that she can finally experience youth and health. Roger is to change Edwina's will so that Terry, her future self, is her sole beneficiary. Roger, unsurprisingly, believes the whole plan is "bananas".
Edwina dies at the law office. The soul-transfer works, but the vase temporarily holding her soul falls out the window and hits Roger. Roger ends up with Edwina's soul sharing his body. She has control over the right side of his body and he the left. She causes him to lose both his girlfriend and his job. Besides being able to hear her thoughts, Roger talks to Edwina's image that appears in mirrors and other reflective surfaces. Their relationship gradually warms up, but both of them want Edwina out of his body. Terry, meanwhile, is shocked to learn that the soul-transference really works, as she only agreed to it to get Edwina's fortune. Terry tries to prevent Roger from reaching the holy man, but when he does, she refuses to cooperate.
When Roger, Prahka and Roger's blind friend Tyrone Wattell (Jason Bernard) sneak into Terry's bedroom, she is waiting with a loaded gun. She intends to kill Roger and pass him off as an intruder, but Roger manages to gain the upper hand. Rather than go to jail for life as a three-time loser, Terry consents to having her soul placed into the body of her favorite horse and let Edwina take up residence in her body as originally planned. The final shot shows Roger and Edwina (who now resides in Terry's body) dancing together.