Tom Thumb and Thumbelina are minor characters in Shrek 2.
Both characters are based on their respective stories, which are in no ways connected with each other.
The two are seen walking together on the red carpet at Fiona and Shrek's wedding ball. They are both accidentally swept up with the debris cluttering the red carpet, and they fail to attend the ball. Tom Thumb pushes Thumbelina in front of him as they are swept up.
Tom Thumb makes an appearance in the comics as the host of the "Happy Endings Fitness Tournament". This contest is held to spread awareness of healthy lifestyles. Although as Tom stated, it's merely just a way to entertain audiences with fairytale characters "sweat like pigs".
- "Tom Thumb" was one of the inspirations for the creation of the fairy tale, "Thumbelina".