Making their romance official, the couple posed for photos at the US premiere, but didn't engage in any PDA with all the flashing lights.
Superstar Mariah, 45, ditched her usual glamorous black gowns for a burgundy figure-hugging dress, and she looked fabulous! She teamed her frock with a cropped black jacket.
Meanwhile, 48-year-old businessman James kept things simple in a black suit and tie.
'Vision of Love' singer Mariah confirmed her romance with James in August when the couple openly held hands while holidaying on the island of Capri.
A source has since told E! News: "They get along amazingly and their communication is always fluid and easy. James is very into Mariah, though, and he wants to spoil her and her children every minute he can. He feels she only deserves the best."
Mariah has twins, Monroe and Moroccan, from her relationship with ex-husband Nick Cannon.
James, who has been ranked as Australia's eighth richest man, is also dad to three children with ex-wife Erica Baxter.
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