Watch: The Flash, Arrow, Supergirl, DC's Legends of Tomorrow - 4 Night Crossover Teaser
The crossover is inspired by the DC Comics Invasion! graphic novel that sees the alien beings known as The Dominators make war with Earth over Earth's metahumans.
The crossover kicks off with the November 28th episode of Supergirl and continues on to The Flash, Arrow and DC's Legends of Tomorrow.
The footage below features The Flash introducing Supergirl to the rest of the CW superheroes, with Stephen Amell's Oliver Queen looking none too thrilled!