How That Lucifer 'Crisis on Infinite Earths' Cameo Came About

Meredith Jacobs
Spoiler Alert Katie Yu/The CW

[Warning: The below contains MAJOR spoilers for Season 6, Episode 9 of The Flash, "Crisis on Infinite Earths: Part Three."]

The devil doesn't lie ... except when he does to keep his appearance in the epic CW crossover a secret.

Tom Ellis' Lucifer did join the Arrowverse heroes (and a few other guest stars) for "Crisis on Infinite Earths," and while fans had a feeling it was coming after he was spotted on set, the actor tried to keep it a secret.

"We were desperately trying to keep it a surprise but then unfortunately some paparazzi spoiled the surprise...so...it was a mild attempt to put the genie back in the bottle," the actor explained on Twitter following the episode.

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"When I went to go and shoot the scene, we were talking on set beforehand — myself and Matt Ryan — and we were like, 'This is so exciting. Wouldn't it be amazing if we could keep this a secret for the fans until they actually see it onscreen that night?'" Ellis revealed to ETOnline.com. That was why he claimed he was in Vancouver for a friend's birthday. "I was just economical with the truth," he said.

It was fitting that Lucifer appeared since he, like other cameos in the crossover, is a DC character. "With these crossover episodes, it opens up a world in which they can really experiment with time and it felt like — if there was ever going to be an opportunity, this was it," he added.

And speaking of experimenting with time, that's exactly what happened given where in Lucifer's timeline the scene took place. "We're playing it as if it's in the five years before the show, Lucifer, started, so when Lucifer spent five years in L.A. before meeting the detective and all those things unfolding," Ellis said. "This is him in his proper playboy, don't-give-a-damn-about-anything stage in his life."

We saw that when he crossed paths with our heroes outside his club. Constantine (Ryan) brought Diggle (David Ramsey) and Mia (Katherine McNamara) to Earth-666 on their quest to restore Oliver's (Stephen Amell) soul. (They'd brought his body back to life via a Lazarus Pit in Hour 2.)

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"With so many Earths already gone, the pillars of magic are crumbling, leaving me the worse for wear, so I can't get us into Purgatory," Constantine explained. "Luckily, I know a guy." Enter Lucifer — and the nods to his own show.

First, he asked Mia what she desired. "I desire to get my father back," she said. "Daddy issues," he replied. "Why didn't you say so?" Constantine filled him in on what they needed, and Lucifer agreed to help because he owed him for Maze. Lucifer then commented that Diggle reminded him of his brother, Amenadiel: "Tall, dark, annoyed by me."

"The devil always sees through on a deal," Lucifer promised, giving them a card to access Purgatory and track the time they had there.

(The CW)

Let's just hope that's not the last time we see Lucifer in the Arrowverse or at least interacting with Constantine.

Arrowverse "Crisis on Infinite Earths" Crossover, Tuesday, January 14, 8/7c, The CW