Secrets won't just come out on this week's all-new episode of The Vampire Diaries.

Clothes will come off.

At least that appears to be the case based on the photos below, all of which are courtesy of "Blood Brothers." Airing this Thursday night, the installment will take viewers back to 1864.

We'll learn the secret that's been hanging over this series since it premiered: How did Damon and Stefan get turned into vampires? Also on our minds, but less pressing: How did Damon get those tricep muscles?!?

You can also check out two sneak peeks at the episode now; while also weighing in on our Vampire Diaries forum: Are you on Team Damon or Team Stefan?

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.