Nicole Kidman has put a sex ban on her fiance Keith Urban.The 'Cold Mountain' actress has told the country singer they won't have sex again until their wedding night - which is rumoured to be taking place in a few weeks time.A source told Britain's Daily Sport newspaper said: "Going four weeks without sex will certainly increase the passion on their wedding night."Nicole reportedly got the sex ban idea from her friend Russell Crowe. The 'Gladiator' star went for months without sex before he married Danielle Spence in 2003.Russell said: "I was determined there would be a lot of pent-up energy on the big night."Nicole is due to marry the country singer Urban in a chapel near Sydney on June 25.Meanwhile, Bette Midler has denied reports she will be singing at the wedding.

It was alleged that Midler had been asked to sing her hit single 'Wind Beneath My Wings' at the ceremony, but she insists she has no plans to appear at the nuptials.