The 22-year-old actress, who made her Oscars debut last week, beat tough competition from other Hollywood beauties to earn the title from GQ magazine.
Barks was an aspiring theatre actress in the Isle of Man before being plucked from obscurity to play Eponine in 'Les Miserables' alongside Anne Hathaway, reported Express online.
Before the ceremony Barks tweeted, "It's very surreal that I may have met all of my living idols in two days!"
Dressed in Valentino, Barks even performed alongwith the rest of the 'Les Miserables' cast at the awards ceremony.