The 32-year-old actress said that like Freeley, she "was sort of a loser in high school."
Greer's screen credits include "27 Dresses," "13 Going on 30" and the upcoming "Traveling," starring Jennifer Aniston. She has appeared on television's "My Name Is Earl" and "Arrested Development."
Greer said she usually plays the best friend or the offbeat character.
"I definitely get the sort of daffy thing," she told the AP. "I don't know why. I don't think of myself as being offbeat, but for some reason those characters come very easily to me."
Ashton Kutcher, who produces the series, will appear in an upcoming episode as a substitute teacher. Jamie Lynn Spears, who plays a student more interested in studying her boyfriend, will also make a guest appearance.
Greer said people are starting to recognize her on the street, and although she likes the attention, there's a downside.
"I guess I get why you have to wear makeup a lot, like when you leave your house," she said.
ABC is owned by The Walt Disney Co.
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