They are shooting the scene in Desolation of Smaug where Kili and Tauriel are having their first real conversation in the dungeons.
In the scene, they talk about a party happening upstairs (something about the stars, I can’t remember). Legolas is supposed to be seen staring at the two of them in jealousy ‘cause he likes Tauriel.
Orlando, however, chose to make this glorious blooper happen by wearing a party hat and calling them sluts.
