Mariah Carey is 'saving herself' until after her wedding to Australian businessman James Packer, a source has sensationally claimed.

The US pop diva has a 'mostly platonic' relationship with her wealthy fiancé, The Sydney Morning Herald reported on Saturday.

'I hear that it has been a mostly platonic relationship,' a friend said. 'According to what I hear she wants to save herself for the wedding night.'

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'A mostly platonic relationship': Mariah Carey (left) is 'saving herself' until after her wedding to Australian businessman James Packer (right) a source told The Sydney Morning Herald on Saturday

Mariah and James, 48, got engaged in New York City back in January after a whirlwind romance of less than a year.

The son of late media tycoon Kerry Packer presented her with a diamond ring with an estimated value of US$7.5 million.

But despite the romantic gesture, one of James' oldest friends reckons that the couple are not overly physical.

Daily Mail Australia has reached out to Mariah's representatives for comment.

Bride to be: Mariah and James got engaged in New York City back in January after a whirlwind romance of less than a year (Pictured at the GLAAD Media Awards in NY last month)

Mariah, 46, was previously married to America's Got Talent host Nick Cannon for six years before their split in 2014.

It has been claimed that the 35-year-old rapper has been 'delaying' the divorce - but he denied the reports in an interview with Extra.

'There's nothing to tell... me and Mariah get along great, and it's a process, nobody is holding nothing up.

'Why would I hold it up? I want her to be happy. She is such a beautiful spirit, and we put the kids first.'

'Delayed' divorce? Mariah, 46, was previously married to America's Got Talent host Nick Cannon (right) for six years before their split in 2014. They share twins Moroccan and Monroe born in 2011

James Packer's first marriage to glamour model Jodhi Meares, 45, in October 1999 lasted just two years.

He later wed model Erica Packer (née Baxter) in June 2007 after dating on-and-off for several years.

They announced their separation in September 2013 and officially divorced later that year.

Meanwhile, the former couple share three children together, daughters Indigo and Emmanuelle and son Baxter.

Mariah has two children with her ex Nick, twins Moroccan and Monroe, born in 2011.