The CW has just released some official photos from the May 17 episode of The Flash, titled “Invincible…” and within those photos is a familiar face.
Yep, that is indeed Arrow’s Laurel Lance, as played by Katie Cassidy, in the episode. How? It’s her other-dimensional Earth-2 counterpart. There, she’s not the Black Canary; instead, she’s calling herself the Black Siren.