The 2 were all over the place -- together -- this weekend, first at Disney World in Orlando and the next day at brunch in Miami.
Kate -- who's 36 -- went to Nick's show at the House of Blues in Orlando Saturday night. Oh, right, he's 23.
It kinda makes sense. She was probably his jam growing up, and she's still just as hot.
The people we spoke with who know them say they're not dating, but they've absolutely hooked up.