Mariah Carey and James Packer
Singer Mariah Carey and billionaire James Packer have been dating since June 2015Reuters/Lucas Jackson

Women and ethnic minorities still get a rawer deal than white men in the entertainment industry, according to Mariah Carey. "I don't think women get a fair deal on anything compared to guys," Carey, who is the biggest-selling female recording artist of all time, told Sky News.

"There is not enough diversity," she insisted. "It is a difficult subject. I have my own opinions and I don't want to offend anyone but women and minorities have had to fight to get equal opportunities for ages, so how can you not agree?"

The American singer is about to set off on her first tour of the UK in 13 years, just after announcing her engagement to James Packer, an Australian billionaire who wooed her with an enormous 35-carat diamond ring.

The mother-of-two also backed Hillary Clinton for the US presidential elections coming up at the end of this year.

She said: "I'm just an entertainer but you know I'm a fan of Hillary Clinton and, of course, I would love to see a woman president."

She would not be drawn on the subject of Donald Trump, the man likely to be the Republican candidate for president in November, saying "I'd like to abstain from that question."

Carey's new tour, entitled Sweet Sweet Fantasy, is due to start in Glasgow in March, stopping in Leeds, Manchester, Birmingham, Cardiff and London, before heading to mainland Europe and South Africa. Fans should "expect the unexpected", on top of a medley of hits from a long career – during which she has sold more than 220m records.

Mariah Carey revealed that she was on the receiving end of a racist attack while riding home on the school bus, when a fellow student spat on her because of the colour of her skin.

What reminded the singer the incident was a scene from her movie The Butler, in which a white woman spits on a black college student during the Woolworth's Lunch Counter sit-in. At a news conference, Carey told reporters: "That actually happened to me. I know people would be in shock and not really want to believe or accept that, but it did. That right there, that was almost the deepest thing to me in the movie because I know what she went through."