A Week In Movies: Thor 2 premieres in London, casting choices surprise fans, veteran stars talk about their new films

The stars of Thor: The Dark World descended on London for the world premiere in Leicester Square this week. Chris Hemsworth, Tom Hiddleston and Natalie Portman posed for the paparazzi and greeted screaming fans before the screening. The film has had terrific word of mouth in advance of its opening in the UK next week and in America the week after. Browse through our photos from the 'Thor: The Dark World' world premiere held at the Odeon Leicester Square, London. Or click here to watch the trailer.

The big news this week is the casting of another UK actor, Jamie Dornan, as Christian Grey in Fifty Shades of Grey, the kinky romance costarring Dakota Johnson. Best known for TV series like Once Upon a Time and The Fall, Dornan replaced Charlie Hunnam (Pacific Rim) in the role. If you're asking yourself 'Who Is Jamie Dornan?' Check out our cheat sheet for 'Fifty Shades of Grey's' Christian.

But this week's most surprising news is that Tom Hardy has signed up to play Elton John in the musical biopic Rocketman. There's no confirmation on whether Hardy will actually sing those iconic songs, but John is re-recording his hits for the movie's soundtrack album, and they'll be used in the film to tell his life story. Read more about the rather suprising casting of Tom Hardy and take a look at him singing in some videos.

Out promoting his new action movie Escape Plan, Sylvester Stallone turned up for David Letterman's show in New York with his wife Jennifer. After greeting his fans and giving a wry nod to the paparazzi, he went on to talk to Letterman about his long-running rivalry with Arnold Schwarzenegger, which has now shifted into a strong friendship. Here's a video of Sly and wife arriving at Letterman and here's the Escape Plan review.

Four Oscar-winning movie veterans were out promoting their new movie Last Vegas this week: Robert De Niro, Morgan Freeman, Michael Douglas and Kevin Kline play retirees who reunite for a bachelor party. They clearly had a great time working together to create a 60-year camaraderie between their childhood-buddy characters. And the comedy is getting great buzz from advance screenings. Watch our video interview with Robert De Niro, Morgan Freeman, Michael Douglas and Kevin Kline.

We had a new trailer this week for Frozen, an animated adventure-comedy based on Hans Christian Andersen's The Snow Queen, about a princess (voiced by Kristen Bell) who teams up with an ice seller (Alan Tudyk) and a cheeky snowman (Josh Gad) to take on her sister (Idina Menzel), who has plunged the kingdom into eternal winter. The film opens at the end of November. Take a look at the Frozen trailer here.

And finally, the latest hilarious trailer for the sequel Anchorman: The Legend Continues was released this week. Will Ferrell, Christina Applegate, Paul Rudd and Steve Carell are all back on board for more ridiculous antics, along with a feisty-looking Harrison Ford. The movie opens in December. Take a look at the latest trailer here.