There had been talks of a crossover between Constantine and Arrow for a while now. Even after the show, fans kept hope that we might see the Hellblazer return in some way. But CW has made it official today. Arrow will need expert help to deal with a supernatural element on the show. And there is no one better to turn to than John Constantine. Reprising his role, Matt Ryan will throw on the trench coat once again for an one off episode. Hopefully, this could lead to an entirely new show based upon the character. But for now, fans will have to simply enjoy seeing Matt in the role at least one last time.