In the Twitter account DCEU Feed (referring to DC Extended Universe), these points were revealed:

"Barry Allen's hair will be kept long for 'BVS'" - which in turn would confirm an appearance in "Batman V Superman: Dawn of Justice."

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"His Flash suit has a Post Apocalyptic look to it"

"Ezra also hinted he's going to have a ripped physique rather than bulky."

The DC Extended Universe will not have any connection to the CW Universe where TV series "Arrow" and "The Flash" inhabit. Thus, there are two versions of "The Flash" and both are Barry Allen.

"The Flash" movie is scheduled to be shown on March 23, 2018 but the expected debut for the character in the DC Extended Universe will be with on "Justice League, Part One" on Nov. 17, 2017.

Cinema Blend reiterates that the hinted appearance of The Flash in "Batman V Superman: Dawn of Justice" may just be a cameo or a reference.

"That doesn't come entirely as a surprise," CB writes, referring to the possible speedy drop-by. "There have been multiple reports of a scene in the film (Batman V Superman) showing security footage of a robbery that was stopped by a 'blur.' However, there was no indication that this scene would actually require Ezra Miller being present."

With regards to the "Post Apocalyptic" theme, theories of time travel and alternate dimensions are likely to emerge. This is a common theme in The Flash and it is still not determined as to which story arc the film will follow.

Comic Book Movie claims that the look will coincide with the overall dark theme of the DCEU.

"The dark and gritty look of the DC Extended Universe means it was always going to have an edgier look than the bright red version from the comics, but this sounds like a very unique direction to take the character in," CBM cited.

A theory from "Darriann" in the CBM article cited that The Flash's post apocalyptic look could be because he's from the future.

"Flash could be the one who comes back in time a few of years to unite the Justice League and warn them of Darkseid's eventual invasion of earth," he explains. "It's not like he has to be from twenty years in the future.He could be Barry from five years in the future and just hasn't received his powers yet in the present day."

TagsEzra Miller, The Flash, movie, Batman v Superman, cameo