|M Digg looking at katie.jpeg|
|Likes/Interests||English, friends, Katie, learning|
Vicky (most of the time)
|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.