The Lonely Doll - Dare Wright - Doubleday (1957)

The Lonely Doll tells the story of a doll named Edith, who lives by herself until two teddy bears, called Mr. Bear and Little Bear, appear in her life. One day, Mr. Bear goes out for a walk leaving the two alone in the house; He returns to find they have rummaged in a closet for dress-up clothing, smeared themselves with makeup, and written "Mr. Bear is just a silly old thing" in lipstick on the mirror. Mr Bear proceeds to discipline both Little Bear and Edith, leaving Edith to worry that he will take Little Bear and leave. Mr. Bear assures her that he will never, ever, leave her.