[Update: Rebecca Hall (The Town) is now up for the role.]

Superhero movies are on the up and up, especially for Marvel Studios who managed to break the record for the biggest weekend opening ever with The Avengers. With the team-up film’s release, Marvel has successfully completed their first set of films and established their brand among the industry’s biggest.

With the success of The Avengers and three solo character sequels on the way over the next two years, there’s so much more to come, but will they be able to top The Avengers? Their first attempt to comes next summer with Iron Man 3, a film which begins shooting this month and one that needs to quickly find a replacement actress.

After the wonderful news of Oscar-winner Sir Ben Kingsley reportedly joining Iron Man 3 as its villain was followed by Guy Pearce joining the cast as geneticist Aldrich Killian, the cast of Iron Man 3 almost got even more impressive when Oscar nominee Jessica Chastain entered talks with Marvel Studios to play another lead character. The character was described as a “sexy” and ‘smart” scientist and Chastain – who enjoyed a career year in 2011 with The Debt, Take Shelter, The Help, The Tree of Life and The Texas Killing Fields – was reportedly the top pick over Diane Kruger, Gemma Arterton and Isla Fisher who were shortlisted for the part as well.

With casting report after interview after rumor all pointing towards Iron Man 3 following the story of Warren Ellis’ “Extremis” storyline from the comics, it was clear that the part Chastain was up for was that of Maya Hansen, another love interest for Tony Stark who happens to be the scientist behind the Extremis tech. In the books, she allies and helps out Tony Stark, eventually joining the S.H.I.E.L.D. organization.

As it turns out, her schedule is simply too busy and Chastain posted the following on her Facebook page:

“Sorry to say that Iron Man 3 isn’t going to work out. My schedule is jammed packed and I can’t fit anything else in. The press announced my possible attachment far too soon. I know many of you wanted me to be involved, and I’m so sorry to disappoint you. Hopefully there’ll be another Marvel film in my future. Shane Black and everyone on the IM3 team are really wonderful. I’m very excited to see the film when it comes out. xx”

Chastain is not leaving on bad terms by any means and I’m sure Marvel Studios would like to work with her as much as she wants to work with them in the future. That being said, this is a big hole to fill last minute, so could we see one of the other shortlisted names jump into the role or someone else entirely?

Whoever plays Maya Hansen might be joining Ben Kingsley, Guy Pearce, Andy Lau and returnees Robert Downey Jr., Gwyneth Paltrow and Don Cheadle.

Iron Man 3 begins principal photography in May and is scheduled to hit theaters on May 3, 2013. Thor 2 comes later that fall and Captain America 2 the following spring.

Follow Rob on Twitter @rob_keyes if want to chat Marvel.

Source: Jessica Chastain