The actresses are currently filming the sequel to Vin Diesel's xXx action movie, and Nina started the war on April Fools' Day (01Apr16), by hiding in a trailer and jumping out to scare the Orange is the New Black star as she stepped inside.

Nina posted a slow-motion video on Instagram of herself leaping towards her co-star as if she was attacking her, and a shocked Ruby went on an expletive-filled rant.

The Vampire Diaries beauty added the caption, "Going to have to wash your mouth out with Soap Missy. **Viewer Discretion is Advised** A Special April fools Edition of my #ScareSeries . Stay tuned for more, from the set of #XXXtheMovie."

On Monday (04Apr16) Ruby posted her retaliation video, in which she printed out a hundred photos of herself and plastered them all over Nina's trailer.

In the clip, Nina walks in and immediately begins laughing, while Ruby follows shortly behind and keeps up with the ruse, saying, "Whoa, what the hell is this, man? Dude this is not OK. Are you obsessed with me?"

Ruby added the sarcastic caption, "When you go to say hi to @ninadobrev but she has 100 photos in her trailer of you and it's awkward because you're trying to be professional.. #seekhelpnina #evillaughofastalker #wherestheshrinetoo #ineedextrasecurity,"

Ruby shared another video of her headshots strewn across Nina's trailer, and in the footage fans could see the photos lined up on the sink, in the bathroom, and all over the bed. She even edited the clip to have Radiohead's Creep playing in the background.

Nina reposted the video on her Instagram account and added the caption, "RUBY!!!! Hahah the music is a nice touch. Oh, it's on. Get ready #TeamDobrev ... About to wreak havoc on @rubyrose #ScareWars."