Nicole Kidman to arrive in Australia today following father's death

Nicole Kidman and Keith Urban will touch down in Australia today following the sudden death of Kidman's father. 

Nicole's publicist and friend Leslee Dart said "Nicole and her family are in shock" while Urban, after cancelling an upcoming US concert, wrote on Facebook "we are in a deep state of grief at the passing of Nic's father and are heading to Australia to be with family".

Meanwhile, Antonia Kidman's husband Craig Marran has endured the difficult task of visiting a Singapore mortuary following the sudden death of his father-in-law.

Dr Antony Kidman, 75, the esteemed Sydney-based clinical psychologist, died from an apparent heart attack on Friday morning in a restaurant at the exclusive Singapore country club, The Tanglin Club.

As Antonia flew from Singapore and her Oscar-winning sister Nicole jetted from Nashville, Tennessee, to be with their grieving mother Janelle in Sydney, Mr Marran visited the mortuary at Singapore General Hospital on Saturday morning and spoke with local police and undertakers from Singapore Casket.

He declined to speak to the media, the Straits Times newspaper reported.

Dr Kidman was in Singapore to visit Antonia, his youngest daughter, Mr Marran, and his six grandchildren.

After early morning exercise he went to the Tanglin Club's restaurant, Wheelhouse, where he suffered the apparent heart attack just before 8.10am.

A doctor at the restaurant attempted to resuscitate Dr Kidman and paramedics took over, but when he arrived at the Tan Tock Seng Hospital at 9.54am he was pronounced dead.

Nicole and Antonia, who over the years publicly pointed to their father's strength and emotional support during their own personally difficult times, are devastated by the sudden loss.

Mr Marran, who married Antonia in 2010, is a managing director of credit capital markets at Scotiabank in Singapore.

Additional reporting by AAP.