Jessica Chastain out of Iron Man 3

Los Angeles - Jessica Chastain has pulled out of negotiations for Iron Man 3.

The Help actress was believed to have been offered a leading role as sexy scientist Dr Maya Hansen, one of the co-creators of the Extremis virus that poses a threat to Tony Stark's (Robert Downey Jr) nanotechnology-equipped suit but scheduling conflicts mean she cannot take part.

She wrote 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 (sic)"

Jessica is currently working on Katherine Bigelow's Zero Dark Thirty, about the hunt for Osama Bin Laden, and she is also set to star alongside Joel Edgerton in double feature The Disappearance of Eleanor Rigby.

Marvel had previously lined up meetings with Diane Kruger, Isla Fisher and Gemma Arterton for the part and it is believed one of them could now take on the role.