Evan Rachel Wood
officially has Bieber Fever.

The "True Blood" and "Ides of March" star covered her second Justin Bieber song Wednesday on "Late Night with Jimmy Fallon" -- singing a fun version of "Baby."

Wood has a history of musical moments. She previously sang Bieber's "U Smile" while doing karaoke in Beijing and recently covered 4 Non Blondes' "What's Up" during Cannes.

How do you think she did singing Bieber this time around? We're thinking it should be her Halloween costume this year.