Keith Urban has bought his pregnant wife Nicole Kidman a $73,000 ring to give her when she gives birth.The country star plans to give Nicole the expensive Cartier Trinity band when the actress, who is expected to welcome her new arrival into the world this month, is in the delivery room.A source said: "It's three rings intertwined, so it's very symbolic."The piece of jewellery represents the three stages of a relationship - yellow gold for friendship, rose gold for love and white gold for fidelity.The source added: "It's three turned into one and that's how it will be with Keith, Nicole and the new baby."Cameron Diaz and Katie Holmes, who is now married to Nicole's ex-husband Tom Cruise, are both said to have the same ring.Meanwhile, Nicole is taking singing lessons in preparation for her new musical film 'Nine'.
The star - who previously showed off her vocal talents in films 'Moulin Rouge' and 'Happy Feet' - will be performing a duet with co-star Penelope Cruz, as well as other numbers with Daniel Day-Lewis and Marion Cotillard.
'Nine' was originally a theatre production about famed Italian director Guido Contini and his colourful love life.