Random Trivia For This Title:
- A fair amount of improvisation was allowed on set; Kat Dennings's calling Stellan Skarsgård "banana balls" was made up on the spot.
- Mads Mikkelsen was considered for the role of Malekith, but he dropped out due to scheduling conflicts with the concurrently filming TV show, [Hannibal] (a role portrayed by Anthony Hopkins in three films, and who plays Odin in this film). Christopher Eccleston was cast instead.
- Tom Hiddleston wore a Captain America suit and did an impression of Chris Evans. Evans later showed up on set and shot his cameo, imitating Hiddleston's impression.
- Christopher Eccleston turned down the offer to appear as The Ninth Doctor in the [Doctor Who] 50th anniversary special to do this film.
- The film was shot under the title "Thursday Mourning". This was also the code name the film was shipped to theaters under. Thursday was named after the Anglo-Saxon name of Thor - Thunres (Thunres Day - Thursday).
- A new language was created specifically for the Dark Elves. Christopher Eccleston (Malekith) and Adewale Akinnuoye-Agbaje (Kurse) had to memorize some of their dialogue in this alien script.
- At the end of September, Jaimie Alexander was injured on the London film set: "It was raining, it was dark outside, it was like 5 in the morning - and I went down a metal staircase and slipped and slipped a disc in my thoracic spine and chipped 11 of my vertebrae. I knocked my left shoulder out of place and tore my rhomboid on my right side... It took me out of filming for a month!"
- Josh Dallas was supposed to return as Fandral but commitment with his TV show [Once Upon a Time] prevented him from returning. He was replaced with Zachary Levi, who was the original choice for the role.
- The filmmakers chose Iceland as the setting for the dark world of Svartalfheim, for its black volcanic landscapes. The name itself, "Svartalfheim", literally means "Black elf world" in Old Norse/Icelandic.
- This is the last film written by Don Payne (who also wrote Thor). He died from bone cancer before the film was released.
- Alan Taylor was so impressed by Adewale Akinnuoye-Agbaje's performance as Kurse, he made Adewale do all his stunts because the stuntmen did not move the same way as he did.
- Loki was originally not going to appear at all, and there was going to be a much greater focus on Malekith and the Dark Elves. Following his popularity in The Avengers, the script was rewritten to give him a bigger role.
- According to Natalie Portman, she was not available to film the post-credit scene where Thor and Jane Foster finally kiss; instead it was shot with Chris Hemsworth's actual wife [?] Elsa Pataky.
- The scene, where Jane Foster and Thor first meet and she slaps him had to be shot several times because Natalie Portman kept 'fake slapping' her co-star to avoid actually hurting him. By the end of it, after about 30 takes, she was slapping him for real. Likewise, where Jane Foster first meets Loki and punches him, Portman actually did hit him. This time around, though, it only took her five takes to get to that point.
- Because of the height difference between the two actors a box, and later a ramp, had to be used in some of the close-up and kissing scenes between Natalie Portman and Chris Hemsworth.
- Chris Hemsworth improvised hanging the hammer (Mjolnir) on a coat hook in a polite manner, after playing with it between takes.
- The Asgard soldier that Loki impersonates as he walks with Thor down the long hallway scene is the same soldier that informs Odin of Loki's death.
- Thor accidentally destroys a statue of his grandfather Bor, and Loki wisecracks that he killed him. In the Marvel comics, Thor actually ended up killing his grandfather as part of a deception by Loki.