Overview
Luna Lovegood is a fictional character in the Harry Potter book series by J. K. Rowling. She first appears in Harry Potter and the Order of the Phoenix, where she is described as having straggly, waist-length dirty-blond hair and a dazed, dreamy look on her face.
Luna is played by Irish actress Evanna Lynch in the film adaptations of Harry Potter and the Order of the Phoenix, Harry Potter and the Half-Blood Prince, and both Harry Potter and the Deathly Hallows – Part 1 and Part 2. On her website, Rowling called Lynch "perfect" for the role.
Lynch had to bleach her hair light blond in order to play the role, and has received critical acclaim.
Character development
Rowling has often said that Luna is the "anti-Hermione", as Luna believes things on faith alone, while Hermione grounds her views on facts and logic. Hermione repeatedly tries to convince Luna that her beliefs are nonsense, but to no avail. This is not to suggest that Luna is foolish; instead, as a Ravenclaw, she believes that "wit beyond measure is man's greatest treasure". Hermione sees Luna as gullible, whereas Luna views Hermione as smart, but limited. Though they have different views, Luna and Hermione eventually become friends.
From Wikipedia (CC BY-SA 4.0).