"What The Cat Told Me"
is a short story by Diana Wynne Jones
A cat settles down on someone's lap and tells the story of how she lived with Old Man, who was cruel, and Boy, who was nice but belonged to Old Man. How she and Boy escaped from Old Man and how she became a nomad, destined to wander for a thousand years, is told in between requests for strawberries and a piece of paper with a string.
It is in several short story collections: Minor Arcana, Believing Is Seeing, Unexpected Magic and Fantasy Stories.