Gwendolyn (voiced by Oleta Adams) is a graceful Siamese cat who appears in The Fearless Four. After her beloved rich owner; Aunt Wanda passed away, Gwendolyn inherited her fortune. But she ran away when her new greedy owners planned to kill her and get her owner's family jewels but she locked them in the basement. After the Mix Max factory was destroyed, she and Buster admit their feelings for each other and sing together with Tortellini and Fred accompanied them.
- Courtney is good friends with Gwendolyn due to them having beautiful singing voices.