The already sprawling cast of the upcoming Arrowverse crossover, Crisis on Infinite Earths, just got devilishly more so - with Lucifer star Tom Ellis reportedly joining the action. The annual crossover has become a staple of the DC/CW shared-universe. This year's event will ambitiously attempt to adapt Marv Wolfman's seminal 1985 storyline and is set to air across five hours. The saga will see the heroes of Arrow, The Flash, Legends of Tomorrow, Supergirl, and Batwoman unite to combat the multiverse-destroying threat of the Anti-Monitor. They will also be joined in that endeavor, for the first time, by the cast of Black Lightning and many more. The impending adventure was more recently seeded in The Flash's season 6 premiere.

Ellis, meanwhile, debuted as the titular fallen angel back in 2016. Despite initially mixed reviews, critical reception warmed across the show's initial three seasons. Unfortunately, shortly after the third season finale, Fox canceled the show. Following an online campaign from his passionate fanbase - of which even Kelly Clarkson considers herself a member - Lucifer was saved by Netflix. Its highly emotional fourth season aired to positive acclaim and firm support from fans earlier in the year. It was soon after announced that the fifth season would be the last - allowing the show's writers to this time conclude the series on their own terms and with an additional six episodes.

Related: Lucifer: 10 Times The Devil Was A Good Guy

According to Twitter user Canadagraphs, fans may not have to wait until that season drops before seeing more of Ellis' Lucifer Morningstar. In seeming revenge for a driver from The Flash refusing to turn down their high beams, they dropped a little scoop regarding the crossover. They made mention of a scene being filmed with David Ramsay (who plays John Diggle), Katherine McNamara (Mia Smoak), and Matt Ryan (John Constantine). Though the scene denotes a crossing over of various points in the Arrowverse timeline (given that Mia is from 20+ years in the future), it is, as the post states, hardly a surprise. All three of those aforementioned actors were recently seen together via set photos. The kicker, however, is that Ellis was also present and dressed in full Lucifer Morningstar attire. Check out the full post below:

Ellis wouldn't be the first actor to jump networks to play the same character within the Arrowverse. And, although Lucifer is more directly inspired by Neil Gaiman's Sandman comics, that version of the character is deeply rooted within DC Comics mythology. It wouldn't even require that much heavy-lifting to introduce the character into the Arrowverse. The concept of Hell was first established within the shared universe in Arrow season 4, when Constantine repaid a debt to the titular vigilante. His method of payment was to retrieve the soul of Sara Lance. The realm was later revisited in Legends of Tomorrow season 4, when Constantine and Nora Darhk undertook a similar quest to save Ray Palmer. As such, the King of Hell appearing would require little exposition.

Then again, it could just as likely be a coincidence. After all, Lucifer season 5 is currently in production and often shoots in Vancouver, where the Arrowverse is also filmed. As such, Ellis may have just popped by during a break in filming. Lending even more credence to that idea is the fact that Tom Welling - who starred in Lucifer as the villainous Cain - will reprise his Smallville role of Clark Kent in the crossover. Therefore, Ellis could've simply been visiting a friend. If the report does ultimately pan out, it won't necessarily be entirely the same version as in Lucifer or make that show Arrowverse canon. It will, however, make for an amusing nod and assuredly give fans even more reason to be excited for what's to come.

More: Arrowverse: Why Crisis On Infinite Earths Is So Important

Crisis on Infinite Earths will begin on The CW on December 8.

Source: CanadaGraphs/Twitter