Olivia Newton-John has postponed a Thursday concert at the Los Angeles' Greek Theatre to be with her ailing mother in Australia.
The singer flew to Melbourne to join family members at her mother's bedside Monday, according to a spokeswoman for Nederlander Concerts, which operates the Greek.
The Greek Theatre show will be rescheduled.
There was no information on the health of her mother, Irene Newton-John, the daughter of Nobel Prize-winning physicist Max Born.
Newton-John's show at Sandia Casino in Albuquerque on Tuesday also has been canceled. She's scheduled to wrap up her summer tour Aug. 29 in Jacksonville, Ore.
The 54-year-old singer successfully battled breast cancer in the 1990s. Her hits include "I Honestly Love You," "Hopelessly Devoted to You" and "Physical." She co-starred with John Travolta in the 1978 hit movie "Grease."