Lars van der Hooten is Mia's very protective Swedish bodyguard. He voices his opinions when Mia is being particularly ridiculous, but goes along with her schemes anyway.
He also turns a blind eye to Mia and Michael when they make out, for which Mia is grateful. He gets on very well with Michael (especially in the first book when Lars seems to know that Michael likes Mia), although he never offers any opinion on Lilly, and becomes friends with Tina's bodyguard, Wahim. Lars also likes Mia's French teacher Mademoiselle Klein. He is known to be a 'big softie', despite his physical appearance.
As her bodyguard, when Mia plots schemes such as pulling a fire alarm to stop Lilly's planned walkout, Lars offered to do it for her to take the rap, but Mia refuses. On her list of people she loves in the seventh book, Lars is sixth, below her dad Phillipe and above her best friend Lilly.