Elizabeth Olsen in GQ: Holy ...

Elizabeth Olsen, sister of Mary-Kate and Ashley, sure grew up fast.

One day, you're just a little kid. The next, you're stripping down in the pages of GQ, talking about indie movie scenes in which you recently got naked.

Gulp.

The classically trained actress, 22, is already generating major Oscar buzz for a strong performance in thriller Martha Marcy May Marlene, due out this fall.

She'll likely be earning buzz of a different sort for posing for GQ in just a bra and a blazer ... not that it would give her pause, given her recent movie role.

Elizabeth Olsen says she didn't flinch about the creepy nude scene in the film in which her body is "offered up" to a man for sex. The star explains as such:

"The movie wouldn't have been as disturbing without it. Taking away someone's sexuality, making it something you don't even own - that's the scariest thing."

That is seriously uncool. Anyway ... on a much more uplifting note, which Olsen sister would you rather - voluntarily, consensually - offer your body to?