Mr. Digg
M Digg looking at katie.jpeg
Status Alive
Friends Remus Lupin
Mr. Carrigg
Katie Sandow
Vicky (Twice)
Enemies Mr. Crocker
Vicky (most of the time)
Veruca Salt
Likes/Interests English, friends, Katie, learning
Dislikes/Hates Being a horrible teacher

Digby Sellers (aka Mr. Digg) is Katie Sandow's cool, laid-back substitute teacher. In his lessons he often implied that he had educated celebrities like Mr. Carrigg and Remus Lupin. He befriended Lizzie's dad in one of the episodes and hates Katie's temporary teacher, Mr. Crocker. In Katie's view, Mr. Digg actually gave great advice and taught stuff that was not only true but also very useful, even when it wasn't in the lesson plan. Plus, Mr. Digg also had his own unconventional way of teaching subjects, and didn't believe in using a lesson plan.