SUDDENLY LAST SUMMER - 1958
Directed by Joseph L. Mankiewicz

Another non-speaking and uncredited part for Rita in this classic black and white film, which also starred Montgomery Clift (but unfortnately not in a scene with Rita).
Rita plays an inmate in "Lions View State Asylum". She appears in two scenes.
The first in the opening of the film she walks across the crowded room full of women until she gets to her rocking chair and gives a nasty look to the women sitting in it until the woman gets up and moves Rita sits down with a smile on her face and rocks back and fourth while knitting.

The final scene comes near the end of the film as Elizabeth Taylor nearly jumps over the top of the balcony, as the inmates watch and cackle eagerly. It's Rita's rocking in her chair, grinning as the camera keeps showing close ups of her face that finally pushes Taylor over the edge. But she is pulled to safety by one of the staff. Rita creates a really scary moment in this short but exceptional non-speaking part.