Arrow and The Flash - Crossover coming in Episode 8 plus Felicity coming to The Flash - best f y

As for how much The Flash will cross over with flagship series Arrow, Kreisberg told TVGuide.com after the panel that it'll happen often on a small scale, but they are planning for a big event later in the season. "Episodes 8 of both shows, Arrow and Flash, are going to be a two-hour crossover event," Kreisberg says. "[Also], in Episode 4, Felicity [Emily Bett Rickards] is going to come to The Flash."