X17 XCLUSIVE - Nicole Kidman Visits A Fertility Clinic!

X17online snapped these exclusive pix of Nicole Kidman visiting a fertility clinic in Santa Monica early last week, sparking rumors that the Oscar winner could be trying for a second child.

Nicole, who's denied a second pregnancy (even though her behavior, slight bump and hair may say otherwise) headed to the building that houses California Fertility Partners, "a Los Angeles based medical practice dedicated to the evaluation and treatment of fertility issues." At 42, it's possible that Nicole will have to use in vitro fertilization to get pregnant, if she hasn't already. And this is the place to do it. We spotted Madonna at the clinic before and during her pregnancy with Rocco, at age 41.

Upon leaving the clinic, Nicole and her assistant/driver were reviewing paperwork -- perhaps tips from the clinic on what to do after treatment?

Seems like Sunday may be getting a sibling sometime soon!