Andrew Kreisberg, The Flash executive producer, revealed during a panel at San Diego comic con that along with a few other new characters, Barry Allen will be joined in season 2 by Wally West. This was also confirmed by the Flash Writers on Twitter a while later.
— FlashWritersRoom (@FLASHtvwriters) July 12, 2015
In the comics, Wally West is the nephew of Iris West, who ran along side Barry as Kid Flash, his sidekick, before taking up the mantle himself. Wally was also the version of the Flash who appeared in the Justice League and Justice League Unlimited animated series, and has always been a fan favourite. This news will surely have fans buzzing, and raises a lot of questions about his existence in the CWverse.