According to Jim - The Mustache

Seizoen: 4 - Aflevering: 17 / 96 - Eerst uitgezonden: 08 maart 2005 - Episode ID: 5751

A hot delivery girl gives Jim some fashion advice, prompting him to grow a mustache, which Cheryl hates. Cheryl retaliates by becoming a brunette - but Jim loves it. After a chance meeting with the girl, Cheryl asks her to give Jim suggestions that will make him look ridiculous.