This is a movie full of fairy-tale references, including famous princesses and fairies.
When Shrek and Fiona trap glowing fairies to use as lamps, they seem to all be dressed exactly like Disney's Tinkerbell, with short green dresses and green shoes.
Shrek, Fiona, and Donkey also drive by Rapunzel's tower, which has a long blonde braid cascading from the window, and Cinderella's castle, which has a gate adorned with a glass slipper.
The princesses' Hollywood Hills-style mansions are also clearly marked by gates with their names on them.