Bette Davis played twins twice: in A Stolen Life in 1946 and in Dead Ringer in 1964. Both aired on TCM recently.
I watched parts of A Stolen Life on Thursday between visits to the laundry room. Good twin Kate is an artist who falls for Bill (Glenn Ford,) Selfish, scheming twin Pat accidentally meets Bill just before his date with Kate and takes her place. Bill and Pat marry. Later a sailing accident creates the opportunity for Kate to steal Pat's life as Bill's wife.
I wish that I had recorded the movie, even though A Stolen Life is not one of my favorite BD films. I don't care for Glenn Ford's pompous, pipe-smoking Bill. The happy ending is too pat and too abrupt.
I haven't re-watched Dead Ringer yet, but I've probably seen it more times than I've seen A Stolen Life. The set up is similar: a scheming twin steals the boyfriend of her sister. But the film takes place several years after that event. Good twin Edith is a struggling bar owner; scheming Margaret is a rich widow. The twins reconnect at the husband's funeral. Later Edith creates her own opportunity to steal a life by killing her twin.
A Stolen Life is more of a romance, and Dead Ringer more of a mystery. The mystery aspects are more realistic. Neither film is great, but they are great vehicles for Bette.