The 25-year-old actress is best known for playing high school students in projects such as TV series -American Dreams- and musical movie -Hairspray- but insists she is nothing like the way she comes across on screen.
She said: "I think that-s a big misconception about me. I tend to play more bubbly people than I actually am. I was never the popular girl. I-m really shy. I-m really just a nerd."
The blonde beauty currently plays a legal secretary in `Harry`s Law` and is hopeful her role on the show will make people realise she is no longer a teenager.
She told the new issue of America`s Maxim magazine: "I`m excited for people to realise that I`m 25 years old and not a teenager anymore ... even though I still look 18 and can`t get into a bar to save my life!"
Brittany is currently single and though she is happy to be on her own, she usually prefers to be in a relationship.
She said: "I`m so single. It`s funny. I-m usually a relationship girl. I love being in love and having a partner in crime. But it`s good to be your own partner in crime. God, that makes me sound like I have multiple-personality disorder!"
The actress also admitted she finds it "weird" when people tell her she`s sexy because she doesn`t think she is.
She said: "It`s weird. I`ve read in magazines where someone like Jessica Alba says, `I`m not a sex symbol. I don`t even think I`m sexy!` "I`m like, `Oh, my God, girl, you`re kidding.` I mean I hate to sound like the stereotypical actress, but if I`m gonna be honest- I really don`t think I am. But it`s nice when other people think so!"