News broke earlier this week that "Arrow" star Katie Cassidy will guest star on an upcoming episode of "The Flash." But Cassidy won't be playing the Laurel Lance that "Arrow" viewers have come to know over four seasons; instead, she'll be playing the Earth-2 version of the character, who goes by the name Black Siren as opposed to Black Canary. Footage of Cassidy filming on "Flash's" Vancouver set has made its way online, and it shows off the actress's complete Black Siren look.

In the comics, Black Siren was the Golden Age version of the Black Canary. Her name was Dinah Drake, and was the mother of the Black Canary, Dinah Laurel Lance. Not much is known about how Black Siren will end up on "The Flash's" Earth-1 or if she'll be friend or foe -- although it does look like Cassidy has a bit of a super villain's swagger in the footage.

"The Flash" airs on Tuesdays at 8 PM ET on the CW.