Arrow Flash
The Flash (left) and Green Arrow are part of The CW's DC superhero universe.The CW

Live action adaptations of DC Comics superheroes are in a period of rebuilding.

The cinematic universe of inter-connected films started with 2013's Man of Steel and will continue in 2016 with follow-up Batman v Superman: Dawn of Justice, before a plethora of other recently-announced films trot out.

Meanwhile on television, popular series Arrow, starring Stephen Amell and based on the character of Green Arrow, has been joined this year by the addition of a series about The Flash, played by Grant Gustin.

There was some confusion over whether the television and film worlds being built by The CW and Warner Bros respectively would be linked, but the recent announcement that Ezra Miller would be playing Flash in 2018 has squashed speculation.

They exist separately... only now DC's Chief Creative Officer Geoff Johns has turned that into 'They exist separately... sorta'.

Speaking to Buzzfeed, Johns explained that the television and film series based on DC characters don't strictly exist in the same universe, but do exist in the same "multiverse".

"We look at it as the multiverse," he explains. "We have our TV universe and our film universe, but they all co-exist. For us, creatively, it's about allowing everyone to make the best possible product, to tell the best story, to do the best world. Everyone has a vision and you really want to let the visions shine through. I think the characters are iconic enough."

The idea of a multiverse exists in the comic book world, explaining away different stories regarding the same characters as being different time-lines or existing in different dimensions.

It's a cop-out of course, but one that has existed for decades in the comic book world. In the comics however, these differing dimensions and time-lines can cross paths, and do so on a semi-regular basis.

This is very unlikely to happen in the case of these film and TV universes.

So for now, everything coming to a cinema remains entirely separate from the heroes you see on the small screen - including Fox's new Batman-prequel series Gotham.

It's a very different approach to what is currently going on at Marvel. There the films and TV shows being produced that co-exist in the same world. For example, ABC series Agents of SHIELD has crossed over with appearances from Samuel L Jackson and ties to recently-released films.

Marvel's slate of TV series being developed with Netflix - starting with Daredevil next year - will also inform their wider superhero universe in this way, though probably with fewer crossovers. At least to start with.