Is Nicole Kidman really pregnant?

First word broke that Nicole Kidman and Keith Urban told their families that they were having a baby over the holidays.
Nicole later denied those rumors by way of her publicist, but now it seems like Kidman and Urban might be hiding something.
PageSix is reporting that Nicole has pulled out of Stephen Daldry's post-World War II Germany drama "The Reader," which she was supposed to start shooting this month, as she is worried about having a miscarriage.
Kidman has suffered miscarriages in the past, so if she is pregnant rest is probably a good idea. Urban was photographed walking hand-in-hand with Kidman over the weekend conveniently covering her tummy with his hand.
Why do celebrities try to hide these things?!