'Arrow' Star Stephen Amell Teases Surprising Costume in "Elseworlds" Crossover

The big Arrowverse crossover is still months away and Arrow star Stephen Amell is keeping fans excitement for the "Elseworlds" event by teasing a surprising new costume.

In a post to his Twitter account Monday night, Amell wrote that he had been fitted for the outfit, but then teased that it was something he "never could've imagined".

"Finally got fitted for my crossover outfit," Amell wrote. "Never could've imagined..."

This isn't the first time Amell has posted to Twitter a tease of his costume for the crossover. Last month, he posted a photo of himself in the makeup chair with a bright green gel on his chest, neck, and part of his face as though he was getting fitted for a mold -- possibly for a new mask. Now it seems the costume has come together, and fans are scrambling to figure out what the crossover costume could be, though Amell followed up that he'd read several responses and none of the guesses were correct.

Given that the "Elseworlds" brand was the name of an imprint that ran from 1989 until 2010 bringing new twists to familiar DC characters and presenting them in "what if..." scenarios, there are virtually limitless possibilities for what Amell's crossover costume could be, though it seems pretty safe to say it won't be the familiar Green Arrow rig that fans of Arrow are most accustomed to seeing him in -- when he's not portraying the hero's civilian alter ego Oliver Queen that is.

This year's Arrowverse crossover is set to be the most exciting to date. Not only will it be the first crossover to not feature all four Arrowverse shows -- Legends of Tomorrow is sitting this one out -- it will also see the introduction of Batwoman, who will be played by a very thrilled Ruby Rose.

"I get to be Batwoman," Rose told Jimmy Fallon. "I feel like the reason I kept getting so emotional was because growing up watching TV I never saw someone on TV that I could identify with, let alone a superhero. [Tearing up] I said I wouldn't do that and I've always had this saying, well not me, Oscar Wilde, which is 'be yourself because everyone else is taken' and so I always lived by that motto and the second motto when I came into the industry was 'be the person that you needed when you were younger' and I feel like one motto sort of led me to the other and I just kept crying about it."

Lois Lane, played by Elizabeth Tulloch, will also be making her Arrowverse debut while Tyler Hoechlin will reprise his role as Superman for all three nights of the event.

The Arrowverse crossover, "Elseworlds", will take place across three nights, kicking off on Sunday, Dec. 9th on The Flash at 8 p.m. ET. It continues on Arrow Monday, Dec. 10th at 8 p.m. and then finishes up on Supergirl Tuesday, Dec. 11th at 8 p.m. ET.