Natalie Portman IS...

Nurse Jane Foster...

in The Mighty Thor
directed by Kenneth Branagh!
Also...
Anthony Hopkins
IS Odin!
Samuel L Jackson
IS Nick Fury!
and
Chris Hemsworth
(George Kirk, James T Kirk's dad, in Star Trek [2009])
as THOR!
Coming in 2011
(All this just to run another pic of Natalie!)