Nicole Kidman will never duet with hubby

Nicole Kidman has vowed never to duet with her husband Keith Urban.

The 'Moulin Rouge' actress - who has a fine singing voice and once recorded a version of 'Somethin' Stupid' with Robbie Williams -insists she will never go into the recording studio with country singer Keith.

Nicole, 40, said: "I would never duet with him! I'm an actress and I think the beauty of two artists being together is that you don't step into each other's fields. We have our work, but most important is our life together, we don't want to blend the two."

The Oscar-winning actress has also revealed she had no idea who Keith was when they were introduced at a black-tie ball for Australians in Los Angeles three years ago.

She added to InStyle magazine: "I didn't know who he was and still don't.

But I'm on a mission to learn who he is! I love that he makes music and I think it's a gorgeous gift he's been given. If he uses it the right way, he can do some beautiful things that contribute to the world."

The couple - who were married in 2006 and are rumoured to be expecting their first child together - divide their time between their ranch in Nashville, Tennessee, and their home in Sydney, Australia.

Nicole said: "We have a place in Australia but we are based in Tennessee because of Keith's work, so we're this hybrid now that we call Tennessean Aussies - and it's a small club!"