During an interview with MTV Kirsten Dunst let slip that she is will be in the next Spiderman movie. 

When asked if she was in or is she out?  She replied:

 “I’m in,” said the actress matter of factly. However, when pressed to make the announcement official, Dunst quickly changed her tone, and rather cryptically added, “I’m not saying anything, I know there’s rumors…”

Your guess is as good as mine…