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Much like Maksim Chmerkovskiy's shirt in the photo below, Kate Upton looked positively tickled pink to be debuting their long-rumored romance by taking a paparazzi-accompanied walk last Thursday in New York. The Sports Illustrated bombshell, decked out in workout clothes, just couldn't keep from smiling as she strolled hand-in-hand with the erstwhile "Dancing With the Stars" pro.

"They are very serious," a source tells People. So serious that Kate, 21, is reportedly planning to settle in New York to be closer to Maks, 33, who has a place in New Jersey.

The couple met through a mutual pal six or so months ago, and while both played the "just friends" card, "Along the way, it turned into something else," explains the insider.

Kate and Maks were first linked in June, when the hypermammiferous blonde rang in her 21st birthday over an "intimate dinner" with the sinewy Ukrainian hoofer.

"That's when it really happened," shares the spy. "It all really started just after her 21st birthday. They just clicked. They have a lot of chemistry together."

Though there have been no hints of an imminent question-popping, "They get along great," enthuses the spy. "They have a lot of fun together."


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