It was recently announced by the Arrow Twitter account that the Arrowverse crossover Crisis on Earth-X was available to stream on The CW website and app, which lead to executive producer Marc Guggenheim making a rather interesting revelation. The executive producer retweeted the Arrow feed's tweet, while adding that he tried to get this four-hour story released as one big movie. Here's what Marc Guggenheim had to say below about why Crisis on Earth-X wasn't released as a huge movie.

"I tried to get this released as a single, seamless, no act breaks, "movie." Maybe even with new material. What stopped us? Ironically, union rules regarding credit."

Past Arrowverse crossovers have been spread out throughout almost an entire week, when there were four superhero shows airing on consecutive nights, but this year's lineup changed things a bit. Now instead of four nights in a row of superhero programming, there are only three, with Supergirl airing on Monday nights, followed by The Flash and Legends of Tomorrow both on Tuesday and Arrow on Wednesday. For this year's crossover, they moved Arrow to the Monday 9 PM time slot to follow Supergirl, with those two episodes airing on Monday, November 27 and then The Flash and Legends of Tomorrow airing on Tuesday, November 28.

Unfortunately, Marc Guggenheim wouldn't elaborate on these "union rules" regarding credit, but the crossover centered on the long-awaited nuptials of Barry Allen (Grant Gustin) and Iris West (Candice Patton), and also featured the introduction of The Ray, played by Russell Tovey, the actor who voiced this character on Freedom Fighters: The Ray, the digital animated series that premiered last summer on CW Seed. While fans can watch all four episodes now on The CW website, it remains to be seen how long they will be made available for.

Having all four episodes in one place to watch is certainly quite convenient for Arrowverse fans, since they would otherwise have to delve through the individual listings on various streaming services to try and track down each episode. When each season will be released on home video formats, fans would also have to buy each one of those seasons to get access to the full crossover, that is unless The CW keeps all four of these episodes on their website, available to stream all year long. Given the popularity of these shows, it wouldn't be surprising if The CW did just that.

Related: Proof That a Smallville / ArrowVerse Crossover Is Happening in Elseworlds?

This week marks the return of most of these CW superhero shows from their holiday hiatus, with Supergirl's mid-season premiere airing tonight, Monday January 15, at 8 PM ET, kicking off four straight weeks of new episodes, while The Flash returns Tuesday, January 16 at 8 PM ET, followed by the series premiere of the new series Black Lightning. Arrow moves to the Thursday 8 PM time slot on January 17, while Legends of Tomorrow returns Monday, February 12 at 8 PM ET, taking over for Supergirl which is going on an extended hiatus. When Legends completes its run on April 9, Supergirl returns with brand new episodes starting Monday, April 16 at 8 PM ET, until its season finale on June 18. Take a look at Marc Guggenheim Twitter for the executive producer's message about an Arrowverse crossover movie.