The first trailer for The Avengers: Age of Ultron - likely to be one of the biggest grossing movies of all time - has been leaked online a week before its intended preview on TV. The clip was supposed to air during the Agents of S.H.I.E.L.D television series but made its way online on Wednesday (October 22, 2014).

Age of UltronIs Iron Man sacrificing himself for Paul Bettany's character Vision?

The source of the leak is unclear, though Marvel appeared to do the smart thing and after making light of the situation on Twitter ("Dammit, Hydra), they released a HD version. 

So what do we learn from the trailer? Well, we get our first look at Ultron, the artificial intelligence and villain of the movie who appears to be wearing the same armour as from the Iron Man comics. Elsewhere, we get an extended look at Robert Downey Jr's Tony Stark, as well as Chris Evans' Captain America kicking down the door of some sort of mountain fortress.

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British fans will be pleased to see Andy Serkis (Lord of the Rings' Golum) making a brief appearance, though Paul Bettany - who is rumored to be playing Vision - is not seen in the clip. Some speculation has claimed that Stark could sacrifice himself in the movie, with Bettany becoming the new Iron Man.

Age of Ultron will also see Scarlett Johansson, Mark Ruffalo and Chris Hemsworth reprising their roles as Black Widow, The Hulk and Thor, as well as Elizabeth Olsen making her first outing as The Scarlett Witch.

The Avengers: Age of Ultron trailer will hit theaters before Christopher Nolan's Interstellar next month. It is released on May 1, 2015. 

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