Nicole Kidman Nicole Kidman

OMG, what a difference a day makes.

Especially if you're a preggers celeb, it seems.

One minute Nicole Kidman's baby curve was all small and subtle.

And now suddenly, out of nowhere, like a babified bolt from the blue, it's mushroomed into a full-on rounded swell.

Talk about a snowball effect...

It seems to us that the astounding transformation has taken place almost overnight.

Here's Nic, who is just over six months pregnant with her first child by hubby Keith Urban, at a recent press conference in New York, where she discussed the issue of violence against women.

And here she is again (right) earlier this month. The difference in her tummy area is startling.Nicole KidmanNicole Kidman

It might be a trick of the light, but it seems to us that she's literally ballooned.

We can hardly believe the lightening journey her bump has undergone from miniscule to mahoosive.

But does the sudden blooming of her bump concur with the old wife's tale that baby boys sit towards the front of the tummy?

Nic and Keith haven't revealed the sex of the bubba yet, so we're just gonna have to wait and see.