Morison, who is best known for having originated the role of Lilli Vanessi in Kiss Me, Kate (1948), later replaced Gertrude Lawrence in the original production of The King and I opposite Yul Brynner.
In the video below, she shows a photo of herself in the role, then sings a snatch of "Shall We Dance" from the score, a cappella.
The video was posted by Scott Feinberg.