Nicole Kidman and Keith Urban have bought a multi-million dollar mansion in Los Angeles, raising speculation the glamour couple's first child will not be born in Australia.

The $US7 ($NZ8.98) million contemporary-style, five bedroom, 4.5 bathroom home is in Los Angeles' exclusive westside suburb, Brentwood.

The Los Angeles Times today reported the home is where Kidman and Urban "expect to welcome their first child".

The Oscar winner appears to be following the pregnancy path of longtime friend and fellow Hollywood starlet, Naomi Watts, who moved to a multi-million dollar home in Brentwood shortly before giving birth to her son, Alexander, in Los Angeles last July.

Prince of Wales hospital and the Royal Hospital for Women, where her sister, Antonia, has given birth to four children, were previously reported as the Sydney locations where the actress would likely give birth.

In March, the couple bought a $US3.47 million, 1000-square-metre home in a gated community in the world capital of country music, Nashville, Tennessee.                                                                                                                                  

Kidman and Urban also paid $US2.45 million last year for a 28-acre ranch and an adjacent three-acre block of land, 50km outside of Nashville, where they plan to build their dream home.

While Kidman and Urban can add real estate moguls to their resumes, another Aussie, Olivia Newton-John, appears to be suffering from the sagging US property market.