Avengers fans don't have to sulk in their misery because they didn't attend this summer's San Diego Comic Con to catch a glimpse of the first trailer of The Avengers: Age of Ultron, because it recently leaked online.

The trailer which director Joss Whedon introduced at the comic con last July, featured the first look at the sequel to the 2012 smash hit. It showed the first look at how the new main villain of the film, Ultron, will look like in the movie. The trailer was laid with voice overs of Captain America, Thor, Tony Stark/ Iron Man and Nick Fury as the Avengers assemble, reports Metro UK.

While the trailer was welcomed with loud cheers from those in attendance at the viewing, several fans were dismayed to find out that the trailer was exclusive to the San Diego Comic Con - that is until now. The trailer was recently leaked online, to the surprise of Avengers supporters.

Watch the trailer below:

The Avengers 2: Age of Ultron will be based on the comic book series following the superhero squad battling Ultron, comic book writer Ed Brubaker noted. It will feature the Ultron, an evil robot that can travel through time and has super-human strength and stamina. The villain will be played by Boston Legal actor, James Spader, who according to Whedon, is the perfect man for the job.

The film will also introduce a new character in Scarlet Witch.

While the squad of superheroes will be returning in the big screen - the Hulk, Iron Man, Black Widow, Thor, Captain America, Hawkeye - and several new characters, one person may not be coming back to the sequel: Pepper Potts.

According to Gwyneth Paltrow, Whedon nor any of his staff or people from Disney have contacted her for the sequel. "Well, no, I don't think so. I haven't heard anything. My phone has not rung for Avengers 2," she said.

The Avengers: Age of Ultron is slated to be released in 2015.