Chastain: Iron Man 3 'isn't going to work out'

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.