Actor Colin Donnell may be returning to the Arrowverse for "Elseworlds," the upcoming crossover, if a new image from Arrow star Stephen Amell is any indication.Amell posted a picture with Donnell on Twitter. The image shows Donnell and Amell standing next to each other. Amell is wearing his Flash costume in the image, indicating that they're on the set of the crossover, which will see Amell play the Scarlet Speedster.RELATED: Arrowverse: Monitor Co-Creator Marv Wolfman Reacts To First Look

It's not clear from the photo if Donnell, who retweeted the photo, is reprising his role or just stopping by the set for a visit. However, the actor has returned to the show on several occasions since his apparent death at the end of Arrow Season 1. Donnell reprised his role as Tommy Merlyn from Earth-X in last year's Arrowverse crossover, but his role in that was rather minor. Considering how late he's joining filming, he may also only play a minor role in "Elseworlds."

This year's crossover is set to introduce a number of new characters and will feature of the return of some fan favorites. New actors making their Arrowverse debuts include Ruby Rose as Batwoman/Kate Kane, Elizabeth Tulloch as Lois Lane and LaMonica Garrett as The Monitor. The event will also see the return of Tyler Hoechlin as Superman. Set photos have revealed that Grant Gustin and Amell will seemingly play an alternate version of the Trigger Twins.

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“Elseworlds,” this year’s Arrowverse crossover event, will begin with The Flash on Sunday, Dec. 9 at 8 pm ET, continue with Arrow on Monday, Dec. 10 at 8 pm ET and end with Supergirl on Tuesday, Dec. 11 at 8 pm ET.