Nicole Kidman and Keith show

THEY are both used to performing but there was only one show on the minds of Nicole Kidman and Keith Urban yesterday.

The couple took Sydney's Royal Easter Show organisers by surprise when they made a low-key arrival with their nephew, Hamish.

Even other showgoers failed to notice them.

But once word had got out that the famous couple were at Sydney Olympic Park, they were flanked by the show's security guards and police.

They took in the woodchop and wandered down sideshow alley where Hamish, who is Antonia Kidman's son, won a stuffed Crazy Frog.

Excited fans Emma Finlayson and Sian Davies, both 16, from the Blue Mountains, were disappointed they couldn't get a photograph or autograph from their favourite star.

"We couldn't believe we saw her in person. It's pretty exciting," Ms Finlayson said.

At lunch the Kidman clan were drawn to the NAB Arena for the action of the Xtreme Korruption, Globe of Death and Lady Cannonball.

They sat among the packed crowd. Kidman gritted her teeth and cheered when freestyle motocross riders flung themselves 60m into the air.

Royal Agricultural Society events and marketing manager John Aitken said it was great to see the couple at the Show.

He said that obviously, like every other visitor to the Show, Kidman and Urban wanted to get cow dung on their boots.