Cast members Tom Hiddleston (L) and Anthony Hopkins greet each other at the premiere of "Thor: The Dark World" at El Capitan theatre in Hollywood, California November 4, 2013. The movie opens in the U.S. on November 8.
Cast members Tom Hiddleston (L) and Anthony Hopkins greet each other at the premiere of "Thor: The Dark World" at El Capitan theatre in Hollywood, California November 4, 2013. The movie opens in the U.S. on November 8. Reuters/Mario Anzuoni

After the unexpected release of the highly anticipated "Avengers: Age of Ultron" trailer, fans were treated with one more surprise. Movie actor Idris Elba dropped a bomb of a spoiler and revealed that his character Heimdall and Tom Hiddleston's supervillain Loki will be returning in the sequel of the 2012 Marvel movie. Ever since the news broke out, fans and media outlets have been wondering how these two characters fit in the storyline that largely focuses on the evil robot and antagonist Ultron.

In his recent interview with British newspaper Telegraph, Idris Elba broke the news. The actor revealed that he will be seen in a scene with actor Chris Hemsworth, who portrays the god of thunder and rain Thor, and Tom Hiddleston, who portrays the fellow Norse god Loki.

Now there are several theories about Loki and Heimdall's appearance swirling around on the Internet. According to Movie Pilot, the answer may be hiding in the clip from "Avengers: Age of Ultron" that was released exclusively in one of the recent Marvel events. The clip shows Chris Evans as Captain America and Robert Downey Jr as Iron Man get into a heated argument while discussing Thor's disappearance. At the same time, they fear their dreadful visions turning into reality.

The aforementioned publication suggests that Loki and Heimdall may appear in Thor's vision, wherein he sees Loki reigning over the kingdom of Asgard. This explains Thor's disappearance from Earth when his superhero friends need him the most. One possibility is that Thor retreats to Asgard to confront his brother. All this and more may see the beginning of the events of "Thor: Ragnarok."

Another possibility suggested by the site is that Loki and Heimdall may not appear until the after-credits scene of "Avengers: Age of Ultron." Considering Loki is set to appear in "Thor 3," Nerdist also speculates that the scene Idris Elba is talking about must be a post-credit scene for "Avengers: Age of Ultron." In 2013 though, Tom Hiddleston confirmed in an interview with Entertainment Weekly that Loki will not be returning to the sequel.

"He's not in it (Avengers: Age of Ultron)," Hiddleston told Entertainment Weekly. The actor said his character Loki has nothing further to contribute to the sequel. "Joss gave me so many wonderful things to do in that first film that we'd only be trying to repeat ourselves, and probably less well in the second one," the actor explained.

Fans must note that Marvel and Walt Disney are yet to confirm the casting news of Tom Hiddleston and Idris Elba in "Avengers: Age of Ultron." Actor's characters Loki and Heimdall last appeared in 2013's "Thor: The Dark World," and fans are undoubtedly excited to see them return to the big screen.

Helmed by Joss Whedon, "Avengers: Age of Ultron" stars Robert Downey Jr as Iron Man, Chris Hemsworth as Thor, Mark Ruffalo as The Hulk, Chris Evans as Captain America, Jeremy Renner as Hawkeye, Scarlett Johansson as Black Widow and more. The movie is set to be released on May 1, 2015.

Video: Avengers:Age of Ultron Exclusive Marvel Event Clip

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For more details on "Avengers: Age of Ultron," read below:

'Avengers: Age Of Ultron': Find Out Which Popular Supervillain Is Set To Return Plus The Mystery Woman From The Trailer Revealed

'Avengers: Age Of Ultron': Joss Whedon On Tom Hiddleston And Idris Elba's Casting Spoilers