Newton-John, 59, married 49-year-old American entrepreneur John Easterling at her home in Malibu, California, according to The Daily Telegraph newspaper of Sydney.

Guests arrived at the house thinking they were attending a Fourth of July Independence Day barbecue to find they were participants in the couple's wedding.

The actress and singer, whose hits included "You're The One That I Want" with John Travolta in 1978, went ahead with the wedding even after a brush fire broke out in a nearby canyon.

A source told the newspaper that the British-born singer and actress, who was raised in Australia, said she had gone through too much in her life already and she was not going to let anything interfere with her happiness. The couple, who began dating last year, are both environmental campaigners.

Newton-John, who was diagnosed with breast cancer in 1992, is also an avid campaigner for breast cancer awareness, leading a three-week celebrity walk along the Great Wall of China in April this year.

She divorced her first husband Matt Lattanzi in the mid-1990s after he had an affair.

In 2005, she was devastated by the disappearance of her boyfriend of nine years, 48-year-old Patrick McDermott, who went missing on a fishing trip off the California coast.

In 2007, Newton-John was back in the headlines when it was revealed that her daughter was suffering from anorexia.