But she is also adamant Peter Jackson, the writer-director-producer of "The Hobbit: The Desolation of Smaug," made the correct choice.
Explaining to reporters at a recent Los Angeles press conference how "The Hobbit" was her favorite book as a little girl, Lilly said she was eager to speak to Jackson and his collaborators about playing a character in the second installment of their "Hobbit" franchise.
"The sylvan elves were my favorite characters in the book and it would be a dream come true to play one. I jumped at the opportunity and picked up the phone very quickly," Lilly recalled.
"And then they said, 'Your character is not in the book.' And I took great pause. As a great fan of Tolkien, I gulped and went: 'What? Everyone's going to hate me.' And it didn't take long for them to completely convince me that it was the right thing to do and it was a good idea," she said. "I think, in his defense, Tolkien was writing in 1937 and the world is a different place today. I keep repeatedly telling people, 'In this day and age, to put nine hours of cinema in the theaters for young girls to go and watch and not have one female character is subliminally telling them you don't count, you're not important and you're not pivotal to story.' And I just think [the filmmakers] were very brave and very right in saying, 'We won't do that to the young female audience, who will come watch our films.' And not just the young female audience, but even women of my own age. I think it is time that we stop making stories that are only about men, especially only about heroic men, and I love that they made Tauriel a hero."
The actress further confided she had some reservations when she learned her orc-smiting character would be romantically involved with a dwarf. That is, until she saw a photo of actor Aidan Turner and realized how handsome he was.
"I agreed to the job under one condition. One condition and they agreed to that condition and that condition was in place for two years and the condition was, I will not be involved in a love triangle," Lilly dished.
"Because any of you who are fans of 'Lost...' I've had it up to here with love triangles and, sure enough, I come back for re-shoots in 2012 [on 'Smaug'] and they go, 'We've made a few adjustments to the love story,'" the actress laughed, referring to how Tauriel becomes the object of affection for both Turner's dwarf Kili and Orlando Bloom's elf Legolas.
Co-starring Martin Freeman, Richard Armitage, Ian McKellen and Benedict Cumberbatch, "The Hobbit: The Desolation of Smaug" has earned more than $500 million since it opened earlier this month. "There and Back Again" -- the third film in the series, which will also include Lilly's character Tauriel -- is set for release in December 2014.