With Supergirl leaving CBS and joining The CW's stable of DCTV shows that include Arrow, The Flash and Legends of Tomorrow, the stage has been set from something monumental in superhero television history. According to Stephen Amell, who kickstarted the DCTV Universe with Arrow back in 2012, the annual crossover event between his show and Grant Gustin's The Flash will likely expand to four with the inclusion of Legends of Tomorrow and Supergirl.
Said Amell, "I think what we'll end up seeing is one giant four-night crossover. No seriously. (to much applause). How we're going to end up doing that...I don't know. But um, this is really um, this is kind of an unprecedented moment in terms of the history of network television. To have four shows, same showrunner. Um, obviously Supergirl is in a little bit of a different universe, but we can fix that. That's one line of dialogue and it's all fixed. So I would suspect Oliver will be meeting Supergirl at some point."
We should receive word on the premiere dates for each of the new seasons of the 4 DCTV programs continuing this Fall at SDCC in July. With any luck, the shows will start filming a few weeks prior and there will be actual footage released as well.