On March 28, 2016 The Flash makes an appearance on Supergirl and here is what we know.
"'Worlds Finest' – Kara gains a new ally when the lightning-fast superhero The Flash (Grant Gustin) suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee, and Livewire, in exchange for her help in finding a way to return him home."
Now with this synopsis it would seem that this will be a one-sided crossover since Barry/The Flash ends up in an alternative reality. If this is the case then it would be hard for Kara/Supergirl to head over to the Arrowverse, but this is comics so who knows.
Now I don't know about you, but this poster looks a little familiar.
This crossover episode hits CBS' SUPERGIRL on March 28, 2016. Will you be watching? Let us know what you think in the comment section below.