An 'X-Men: Apocalypse' trailer from the San Diego Comic-Con has been leaked online from the first five weeks of filming. The movie is set to premiere May 27, 2016.

According to IGN, several trailers were shown at Comic-Con and then released online, including Batman v Superman. X-Men: Apocalypse and Deadpool were not released to the public.

"The reason you don't see footage out that far is you run the risk of it getting stale", said Hutch Parker, former president of production for 20th Century Fox, as quoted by IGN.

The X-Men trailer that was leaked is low-quality and features a lot of dialogue. X-Men Apocalypse will conclude the trilogy started by X-Men: First Class and X-Men: Days Of Future Past.

"I'd say it really isn't intended to be leaked. It's really intended to excite a core," said Parker, as quoted by IGN. Parker also mentioned to IGN that the trailer will not be shared for a long time.

According to Screen Rant, 'X-Men: Apocalypse' will be based on the ancient mutant villain Apocalypse seeking to wipe out humanity with the help of "sentinels". They will be known as the Four Horsemen of Apocalypse which includes Angel, Psylocke, Magneto, and Storm.

"It takes place 10 years after Days Of Future Past in a completely different world," said Director Bryan Singer, as quoted by The Daily Beast.

The trailer begins with Jean having nightmares about an apocalyptic future and Professor X tells her it is just a dream but it's not. In the trailer you can also see Magneto with old soldiers in the forest. You can also see the Apocalypse's costume and his blue face.

Entertainment Weekly has released photos of the cast of X-Men featuring Apocalypse played by actor Oscar Isaac. The cover also features Magneto played by Michael Fassbender and Psylocke played by Olivia Munn.

X-Men: Apocalypse will have the returning cast of Days of Future Past as well as new characters including Alexandra Shipp as Storm, Sophie Turner as Jean Grey, Ben Hardy as Angel, Tye Sheridan as Cyclops, and Lana Condor as Jubilee, reports Superhero Hype.

James McAvoy is returning as Professor X, Jennifer Lawrence as Mystique, Nicholas Hoult as Beast, Evan Peters as Quicksilver, Rose Byrne as Moira, and Lucas Till as Havoc.

There is a teaser in the trailer that could possibly be a very important plot twist involving Professor X.

Singer posted a photo on Instagram of Storm looking over Cairo. ComicBook reports that Storm is a thief in Cairo before being recruited as one of the Horsemen.

In the comic book Storm is worshipped as a goddess in Cairo before she is recruited by Professor X. Screenrant reports that it's still unclear how much of the comic book will be shown in the movie.

Deadpool is set to open Feb. 12, 2016 and Gambit on Oct. 7, 2016.