News broke today that "Arrow's" Katie Cassidy will be heading to both "The Flash" and "Vixen" later this year.

RELATED: "Arrow" Echo Kellum Promoted to Series Regular

Katie Cassidy currently plays Laurel Lance on The CW's hit show "Arrow." Throughout the last four seasons her character has transformed from an up and coming lawyer to Star City's assistant district attorney, and a fully developed superhero, the Black Canary.

While characters from "The Flash" have met Laurel before, when Cisco (Carlos Valdes) and Joe West (Jesse L. Martin) traveled to Star City, she has never been on "The Flash." All of that is about to change, as Katie Cassidy has been confirmed to be appearing in episode 22 of this season of "The Flash."

According to TVLine, Cassidy will be playing a character from Earth-2 named Black Siren. 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. Either way, it will be fun to see Cassidy play another character in the DC TV universe.

In more crossover news, Cassidy will also be voicing Laurel Lance on season two of "Vixen." According to EW, season two of "Vixen" will explain how Laurel and Mari McCabe (Megalyn Echikunwoke) first met.

Cassidy's episode of "The Flash" will air Tuesday May 17 on The CW at 8 p.m.