British actor Tom Hiddleston was mobbed by fans as he arrived at the world premiere of Thor: The Dark World.

The 32-year-old, who has reprised his role of Thor's brother Loki for the third time, received the biggest cheers with crowds chanting his name and holding up Loki banners, as he walked up the red carpet outside London's Odeon West End cinema alongside co-stars Chris Hemsworth and Natalie Portman.

"I am surprised people like Loki so much. I've been asking myself that three times now," he said.

Hiddleston, who previously portrayed Loki in the first Thor film and Avengers Assemble, said it was "fantastic" returning to his mischievous alter-ego.

"When I first started playing the character, I threw everything I had because I thought it would be the only chance I'm going to get. You never think, 'I'll save something for the next time' and then there's a second and third time. It was so interesting to evolve and change him."

Hemsworth, who plays Norse god Thor, said he wanted to find new facets to his character in each film.

"The challenge is to improve on what you've already done and we have managed to do something new," the 30-year-old said.

Portman, who is back as astrophysicist Jane Foster, teamed a black top with a floor-length silver skirt by Dior.

She said: "Jane is such a multi-faceted character. You get to see a real woman - all the different sides in different situations."

The film's British stars - Idris Elba, Adewale Akinnuoye-Agbaje and Christopher Eccleston - joined Kat Dennings and Stellan Skarsgard at the premiere.

Eccleston, who shows off his villainous turn in the Marvel movie as Dark Elf ruler Malekith the Accursed, joked: "Nobody spoke to me on set because I was the bad guy. I was scaring everyone. I think he was misunderstood actually."

The sequel, set after the events of 2012's Avengers Assemble, sees estranged brothers Thor and Loki join forces to defend Asgard from Malekith and the Dark Elves.

Thor: The Dark World, which was partly shot in London, opens in cinemas on Wednesday, October 30.