This is a little bigger than some news, since the Ray will be the first gay male hero that the DCTVU (There must be an easier name for it than that) has featured;
The Ray will debut in the crossover (which will also include Arrow, Supergirl, Flash and the Legends of Tomorrow team), before getting a four episode animated series "Freedom Fighters: The Ray", and will be played by openly gay British actor Russell Tovey, best known perhaps, aside from an appearance in Doctor Who as Midshipman Alonzo Fraim in "Voyage of the Damned" (And later making a brief cameo as a potential new boyfriend for Captain Jack in "The End of Time") as George, a werewolf in the supernatural comedy-drama "Being Human" (The UK version that is).
Some promotional art was put together by Phil Jimenez, in the style of the old multiple Earth crossover covers to publicise the event, which also hints that it will take place around the wedding (or not) of Barry Allen and Iris West.
(Click to embiggen)
Now, understandably, there has been some eyebrows raised at the decision, in the current political climate in the US, to make the Arrowverse/Supergirl crossover be based around Earth-X; the DC Earth where the Nazi's won World War II, and where we will see several Nazi versions of established heroes, so we'll have to see how THAT is handled (Secret Empire is a low bar to clear, but here's hoping)
As a geeky aside; Earth-X debuted in 1973, when WW was less than 30 years finished, as a separate home for a number of Quality Comics characters DC had acquired, like Uncle Sam, the Human Bomb, Doll Man, the Ray and Phantom Lady. They were folded into the WWII heroes following Crisis on Infinite Earths, though more modern takes on them have surfaced a time or two in the last couple of decades.