Spencer Locke will be making an appearance on The Vampire Diaries.
Her characters name is Amber Bradley. (Loved her as K-Mart in Resident Evil)

Here is some info on her character from TV Guide.

Spoilers

Turns out Amber is a beauty pageant contestant who will compete in late April episode against Elena (Nina Dobrev) and Caroline (Candice Accola) to be the next Miss Mystic Falls. This sounds like a fun follow-up to the bachelor auction Damon (Ian Somerhalder) and Alaric (Matthew Davis) will take part in when the show returns with a new episode (“A Few Good Men”) on March 25.