The couple was spotted enjoying a late dinner at Italian eatery Carbone on Sunday, May 1, sparking fresh rumors of a budding romance.
Both stars kept it casual chic, with Kate rocking a sheer purple top and light blue, flared jeans. Nick also wore jeans with a black denim jacket and a forest green shirt.
The couple left the restaurant separately and seemed relaxed and happy to be there.
Kate, 37, was first linked to Nick, 23, back in September 2015, but last month Nick told Now magazine the two are not seriously involved. "We're very good friends," the former Disney star said. "Whatever it was, I think it's between her and me. I'll just leave it at that. But it's never simple, with anything."
The pop star added, "I'm very single right now. It's circumstantial—it just sort of happened that way. In the last couple of weeks I've become even busier doing promotional stuff, so there's literally no time. I wish I had something very juicy but at the moment I don't."
There is a lot to read between those lines, but Kate indicated she moved on from Nick when she posted Snapchat videos of her date with football star JJ Watt.
Still, it's clear she and Nick shared something really special. Nick basically said as much when he spoke to Complex about his time with the "Almost Famous" actress. "Kate's incredible," he told the magazine. "We had an unbelievable connection as two humans who just admire things about each other, and see something in each other that's beautiful."
Ever the gentleman, Nick added, "Out of my best effort to respect her and her privacy, I'm not going to say if we had sex or not. But we did have a beautiful connection. Even now I have so much admiration and respect. She's amazing."