The Avengers: Age of Ultron official trailer hits YouTube following Marvel leak

'It's the end, the end of the path I started us on'

The Hulkbuster armour makes an appearance (Marvel)

Marvel has released the first teaser trailer for The Avengers: Age of Ultron a week early after it leaked online, seeing the superhero team devastated by James Spader's supervillainous Ultron.

The words 'I had strings but now I'm free' from a Pinocchio song creepily score the trailer (somewhat appropriately given that was a Disney film too, oh how far we have come), as Iron Man, Captain America, The Hulk, Black Widow and more regroup to face a a super intelligent robot.

The clip was set to debut during Marvel's Agents of SHIELD on ABC next week, but after a low-res version found its way online Marvel decided to post it in full HD.

The studio made light of the situation on Twitter, tweeting "Damnit, Hydra." shortly before.

Notable events in the trailer include Ultron appearing to don Iron Man's Hulkbuster armour, Andy Serkis popping up for the first time and Captain America heading to a mountain fortress, suggesting the return of the many-headed Hydra.

"It's the end, the end of the path I started us on" Tony Stark says during the trailer, though it definitely isn't as Robert Downey Jr. is tied down to a contract for a third Avengers movie.

He recently acquired a giant 'A' symbol from the first Avengers movie, telling BBC Radio 1: "On the last Avengers, there's this scene where there's this 'A' which is probably 30 feet tall, and I'm looking at it, and we're shooting in England, and I go, 'I need that in my office in Venice."

James Spader voices Ultron (Marvel)

Joss Whedon's first instalment is the third highest-grossing film of all-time, taking a vast $1.5 billion at the box office in 2012.

Chris Evans, Scarlett Johansson, Mark Ruffalo and Chris Hemsworth also return from the original, along with newcomers Aaron Johnson and Elizabeth Olsen who play Quicksilver and The Scarlett Witch respectively.