Street artist Posterchild, who hails from Toronto but has recently been spending time in New York, just proposed to his girlfriend... via street art, of course. He says his lady love Sonja, "thought she was just helping me out with another street art project; I kept this covered until after it was installed and after the unveiling I was expecting some kind of reaction — but it took a little while to convince her that this was a proposal for real, and not just some art project!"

Torontoist talked to the Sonja, who said yes, and she told them: "I had absolutely completely no idea that he had been planning this. This is so old hat for us: we go out almost every night, and he puts things up, and I document, or I help him carry things. And he was like, 'Oh, we'll walk around and get a drink, and while we're out I'll throw something up that I have to put up.'" In fact, she thought it was part of a project he had recently been talking about, in which he'd put up signs "with sayings that would make people feel uncomfortable."

The big question was popped at the 23rd Street station, where Sonja says she "stood there with a video camera, filming." Watch that video after the jump...