Carey, 45, and Packer attended the New York City premiere of "The Intern" and posed for photos while supporting the Anne Hathaway-Robert De Niro-starrer comedy, reported E! Online.
Carey wore a purple dress with a sequined leather jacket while Packer kept things simple and classic with a suit and tie.
"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," a source said.
Carey split from TV host husband Nick Cannon last year.