Katherine Evelyn Anita "Katie" Cassidy (born November 25, 1986) is an American actress. She portrays Laurel Lance/Black Canary in a lead role in the first four seasons of Arrow, and also special guest starred in the first season of The Flash. She reprised her character in a guest starring role in the first season of DC's Legends of Tomorrow. She portrayed her Earth Two equivalent, Laurel Lance/Black Siren, in a guest starring role in the second season of The Flash. She will also voice her character in a major role in the second season of Vixen.
Cassidy signed a deal that would make her a series regular across all of the Berlanti shows. As of 2016, she has the freedom to move across the fifth season of Arrow, the third season of The Flash and the second season of DC's Legends of Tomorrow.