Marc Guggenheim is one of the architects of the Arrowverse and an executive producer on DC's Legends of Tomorrow. He's also good for the occasional tease tweet and tonight is no different. We started hearing a few months back that the show wanted Matt Ryan to reprise his role of John Constantine. Ryan appeared as DC's resident chain-smoking master of the dark arts in his own NBC series for one season, then popped up on Arrow to help save Sara Lance (Caity Lotz) and even provided the voice of the character for the Justice League Dark animated movie. Ryan has also committed to voicing the character in the upcoming CW Seed animated Constantine series… so it was no surprise when word came down that he would be showing up on the Waverider at some point this season.
A few hours back, Guggenheim posted an image from inside the editing room as they work on an upcoming episode of Legends of Tomorrow. On the screen we see Ryan in the familiar beige trench coat of Constantine, talking with Ray Palmer (Brandon Routh). The fact that episode 310 is being filmed this week, it's possible that the footage is dailies from the episode or from 309. Either way, we can expect to see Ryan show up at some point after the crossover.
DC's Legends of Tomorrow airs Tuesdays at 9 PM on the CW.