Who is Donna LaDonna from The Carrie Diaries and what is their importance?

Donna LaDonna is one of the most popular girls in school. She is a cheerleader, and Sebastian is her boyfriend. When Sebastian takes an interest in Carrie, Donna begins acting out against Carrie, which Carrie initially believes is revenge. Carrie later discovers that Donna has disliked her since kindergarten.

Donna and Carrie become closer when they attend a photography class together at the local library. In the end, it is because of Donna that Carrie meets Samantha Jones when she arrives in New York City.