A Stolen Life and 1964's Dead Ringer, both times appearing as a woman who took the place of her twin sister after that sister died. The Scapegoat, made five years before Dead Ringer, is another movie about a character impersonating someone to whom they bear an exact resemblance, although in this case it's Alec Guinness in the dual role, and Davis hamming it up as part of the supporting cast. She plays a morphine-addicted countess who appears in three scenes and is mostly bed-ridden, but she makes the most of the part, and is a catty, cackling contrast to the dry restraint of the rest of the movie.
The story is a little slow, and the direction is a little too subdued, but overall The Scapegoat is a nice thriller with a satisfyingly ambiguous ending. It finds Davis in her scene-stealing supporting-role mode, although she's given prominent billing in the credits. Mainly she's here to liven things up a little and offer an amusing counterpoint to the buttoned-down Guinness. On that count, she succeeds, and the movie mostly does as well.