The tour is based on Carey's album Charmbracelet, on which she embraced R&B and hip hop fully after the disastrous release of the album and film Glitter.
The singer, who broke the record of the Beatles for the amount of US number one singles — 13 in all — was rumoured to be in the midst of a breakdown in 2002.
“The whole year — and all the rumours and all the hoopla and all the lies, and actually working myself into the ground — [brought me] to the point where I was hospitalised from exhaustion,” Carey told the BBC.
“That turned into rumours that I had tried to kill myself.”
Carey has poured a great deal of effort into reinventing herself for both the tour, and the album it is based on, after her career took a major plunge two years ago.
Carey had married her boss at Sony records, Tony Mottola, in 1993. But after the two split up some nine years later, the singer became desperate for a new label — and accepted an $80m deal from Virgin, the biggest record contract in history.
The first project was to be movie and album Glitter, the story of a rising star, which had remarkable similarities to her own life.
But the film was panned by critics and the album — released on 11 September 2001 — failed to sell, and Carey's career went into spectacular freefall.
“That project with Virgin was very much a snap decision that I made… I was under a time constraint due to the fact that I was trying to get away from a label which I had been very successful with, but was very difficult because of the personal relationship that I had with the head of the label,” Carey stated.
“Then it was just a complete and total stress-fest.
“I made a total snap decision which was based on money, and I never make decisions based on money. I learned a big lesson from that.”
Indeed, Glitter was such a disaster that it nearly ruined parent company EMI Records, and Carey was dropped in early 2002 — at a cost to Virgin of $28m.
Shortly afterwards, Carey went into a painfully public breakdown.
She suffered bizarre promotional appearances, and posted a string of rambling messages on website.
In the meantime, acts like Shania Twain and Destiny's Child had made major impressions on Carey's key audience, and there was speculation over whether she would still have much impact.
There was also much pressure on the record company that had picked her up, legendary hip hop label Def Jam.
Although Carey's music had dabbled in hip hop since 1995 — with the track “Fantasy” from the album Daydream — to many she remained synonymous with the big ballads that made her famous, such as “Hero,” “Anytime You Need A Friend” and “Without You.”
Charmbracelet, however, with its vast number of collaborations, did much better business than Glitter — although its sales were still much behind the likes of Music Box, released when Carey was at her peak.
But the tour has done very well, promising a more “intimate” evening, and has been extended.
Carey contended that her style now was an answer to her critics, especially those who had argued she was limited to sugary ballads.
“I've worked with everybody from Pavarotti to Ol' Dirty Bastard,” she said.
“I've worked with Snoop, Jay-Z, Mobb Deep, Nas — countless people that I admire… to me, doing collaborations is part of making music.
“I think it's cool, because it exposes hip hop to a broader audience.”