Lilly's character, Tauriel, is an elf warrior and head of the Elven Guard, who Lilly describes as "slightly reckless and totally ruthless and doesn't hesitate to kill."
Director Peter Jackson and co-writers Fran Walsh and Philippa Boyens got flack for the male dominated first film and wanted to bring more girl power into the boycentric world of The Hobbit so they created Tauriel and also expanded the world of the elves.
Even though she's nervous about being thrust into The Hobbit's fandom, Lilly is ultimately confident that fans will love Tauriel mainly because of the knowledge Jackson, Walsh and Boyens have about this world.
I think if anyone knows how to respect Tolkien, it's Peter, Fran and Phil. And Tauriel fits perfectly in that world.
We shall all see how it works when The Hobbit: The Desolation of Smaug hits theaters on December 13th.