Yup, the Kat is out of the bag.
On The Vampire Diaries Season 5 Episode 15, Caroline will let her friends in on the little secret that Elena has actually been Katherine for a very long time now.
This will lead them all to ask the same question many viewers have been pondering for weeks: How did they not pick up on this?!?
Talk about a major OOPS, huh? Watch the latest sneak peek now:
The CW has also released a number of photos from "Gone Girl."
Watch The Vampire Diaries online if you need a refresher and click through these episodic images now: