Here’s another short but very sweet teaser trailer for the hotly anticipated crossover when The Flash (Grant Gustin) makes a guest appearance in CBS’s Supergirl. And they do what always happens when the Scarlet Speedster runs into a friendly Kryptonian – they have a race!
— Supergirl (@supergirlcbs) March 17, 2016
The Flash and Supergirl crossover episode, called “World’s Finest”, is set to air in the States on Monday 28 March on CBS. Over here it’ll be on Sky 1 sometime in early June (if we’ve done our maths right and Sky doesn’t show two episodes a week or something).
“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.”