Mariah Carey is blaming her breakup with her Australian billionaire fiancé James Packer on a Tommy Davis, a former chief spokesperson for Scientology, according to reports in the US media.

Carey, 47, is said to have called the wedding off last week, and on Monday night was spotted out at a Halloween party without her $10 million diamond engagement ring.

Mr Packer was said to be concerned at her spending, and at the intrusion into their lives through her reality television show.

The singer is now reported by gossip website TMZ to be locked in “separation talks” with Mr Packer’s lawyers, seeking a Los Angeles home. The site also claimed Carey is demanding a $50 million “settlement” after she relocated to LA to be with Mr Packer, and cancelled the South American leg of her tour after an incident on his yacht in Greece which left her “traumatised.”

And it is reported that she blames Scientology for contributing to her breakup with Mr Packer, after he hired the former spokesman for the Church, Tommy Davis, to manage his US business affairs.

Mr Davis had a famously explosive encounter with John Sweeney, a BBC journalist, for the 2007 Panorama documentary Scientology and Me.