After secretly rounding up the singer’s close friends for a private dinner at Eleven Madison Park in New York, James, 48, reputedly proposed to Mariah, 45, with a 35-carat diamond ring.
The jet-setting couple has been dating for less than a year after originally meeting in 2014 through mutual friend and James’s business partner Brett Ratner at a movie premiere in Aspen.
No date has been announced for the wedding, but it will be the third marriage for both Mariah and James.
James was married to Jodhi Meares and Erica Baxter, while mum-of-two Mariah was hitched to Nick Cannon and Tommy Mottola.
James also has three children to Erica: Indigo, Jackson and Emmanuelle.
Close sources say James had been aggressively chasing Mariah for months before they started dating.
Fresh out of her turbulent marriage to Nick, Mariah was said to be less than impressed.
But by June, the story had changed and the celebrity couple dubbed “Jamiah” in many circles was more than happy to flaunt their new romance for the cameras.
In July, 2015, Mariah was snapped almost falling down the steps of James’s mega-yacht while her boyfriend was busy soaking up the sun.
Mariah then performed at James’s New Year’s Eve concert at Crown Casino in Melbourne.
“Spectacular, handsome… I don’t even have words for the man who introduced me tonight,” Carey said of James on the night.
The globe-trotters have set a cracking pace as their “caravan of love” has traversed from Macau to Sydney, Las Vegas to Aspen and New York to Portofino.
James even took Mariah to the Western Wall in Israel.
An insider told E! at the time: “There is only one place at the Western Wall where men and woman can stand together and it was meaningful for him to take her there so that they could share this very intimate moment as a couple.”
Another source adds, “It was more a spiritual journey then anything. He is aware Carey has the world at her fingertips but he likes to find things that she has never experienced.”