Though Tanka and Carey seemingly got together right after her split from billionaire James Packer, the source says the two "weren't together when she broke up with James." They are now, however, in a "proper relationship."
Spending the holiday together has also brought the couple closer. ET's source reveals that Tanaka gifted Carey with jewelry for Christmas, while she often lavishes him with gifts.
Earlier this week, a source told ET that Carey and Tanka will take their romance even more public, as he will be the singer's "New Year's kiss" after she performs on Dick Clark's New Year's Rockin' Eve With Ryan Seacrest on Saturday in New York City.
"She's into him now," the source added.
Find out what Carey gave Tanaka for Christmas in the video below.