Could a DC Television Universe expand across networks? In an "Entertainment Weekly" (via KSiteTV) profile of "The Flash" and "Arrow" co-showrunner Greg Berlanti, the writer/producer/director mentioned that one of his in-development DC Comics television projects -- "Supergirl" -- could have the potential to "enter the worlds of [Arrow](series:720988) and The Flash." The unique aspect of the reveal is that "Supergirl" currently has a home at CBS, while "Arrow" and "The Flash" are on The CW.
While network crossovers aren't unprecedented -- "The Practice," which aired on ABC, once crossed over with FOX's "Boston Public," among other examples -- it's certainly not common. It also potentially opens up the door for other DC Comics-based shows to be in the same shared universe.
That said, it wouldn't be the first time all three characters have been in the same live-action series. Versions of [Supergirl](series:2246875), The Flash and Green Arrow all appeared over the course of "Smallville," the long-running DC Comics-based series on The CW.
Written by Ali Adler and executive produced by Adler and Berlanti, "Supergirl" focuses on a 24-year-old Kara Zor-El, who decides to embrace her superhuman abilities and become a hero after years of hiding her superpowers. The series is also set to include characters Cat Grant, James Olsen, Winslow "Wynn" Schott and Hank Henshaw.