With the success of Iron Man 3 and The Avengers becoming one of the highest grossing films of all time, producers are working on a sequel for ensemble cast of superheroes.

Rumors of the cast and plot have been rampant amongst Marvel's fans and writer/director Joss Whedon revealed in December 2012 that he has already completed an outline storyline for The Avengers 2.

Iron Man 3 saw Tony Stark's character hang up his Iron Man suit, and fans are not sure about Robert Downey's future with the Iron Man movie series. However, Downey did sign a deal with the studio for both The Avengers 2 and The Avengers 3, so Tony Stark will indeed return as the Iron Man for the upcoming flicks.

Actor Hugh Jackman who plays the Wolverine, has expressed interest in his character being added to the Avengers ensemble. He said he would love to be part of the film, which is scheduled for a 2015 release date.

"I'm in for it, I'm totally up for it because I think that would be really exciting for fans," Jackman said.

According to Worst Previews, Jackman allegedly spoke someone at Marvel to get Wolverine involved in the Avengers franchise.

"I said, 'Can this happen?' and he goes 'Look, it's not gonna be easy.' But I'm optimistic, I find it impossible that there's not a way to bring Iron Man, all the 'Avengers' characters, Wolverine, the 'X-Men' characters, Spider-Man, and somehow get them together," he said.

The Avengers starred Marvel comic fans' favorite characters: Iron Man, Thor, Captain America, The Hulk, Black Widow and Nick Fury.

Some new superheroes touted to be added to the The Avengers 2 are Quick Silver and his mutant sister Scarlett Witch.

Fans immediately speculated that Irish actress Saoirse Ronan play the role of Scarlet Witch in the sequel. She had previously expressed that she would love to be part of the film, telling The Mary Sue: "I love Joss and I love those films, and I love his handle on them and how he portrayed these kinds of superheroes. I think it's very different from what anyone else has done. So yeah, I'd love to be in it."

However, the 19-year-old dispelled rumors of her taking on the role of Scarlet, telling The Irish Post: "That's not happening, no! I think that was just one of those little rumors floating about."

Some fans are pondering whether Andrew Garfield of The Amazing Spiderman will join The Avengers 2 cast. According to ComicBookNews, Garfield said he wouldn't mind appearing in the film.