The DC television universe is taking a step closer to full integration; CBS has announced that The Flash, played by Grant Gustin from the CW series, will appear in Supergirl, on CBS in the Monday, March 28 episode.
There had been speculation that this might happen since the first announcement of the Supergirl series; the same team is producing both shows (and the CW’s Arrow and Legends of Tomorrow, see “New ‘Legends of Tomorrow’ Trailer”). “We are so incredibly excited to announce something that we have dreamed of happening since we starting making Supergirl – The Flash and Supergirl are teaming up,” Executive Producers Greg Berlanti and Andrew Kreisberg said. “We want to thank Grant Gustin for making the time to come visit (on top of his already immense workload) and all of the folks at CBS, The CW, Warner Bros. and DC for working this out.”
Presumably at some point the visit will be reciprocated with Supergirl appearing on The Flash, and there also the other DC-based shows on The CW that could also be brought into play.