Last week, the Princess of Wales went on a field trip with some schoolkids. They took a bus to the National Portrait Gallery and checked out a new interactive exhibition for children. In the days after the field trip, we learned that it was likely something NPG put together with the school, and NPG likely asked their royal patron to ride along, which is exactly what Kate did. Hilariously, this outing came just a few days after Kensington Palace briefed far and wide that they would no longer speak about Kate’s clothing or provide fashion IDs. Those briefings did not go over well, and neither did Kate’s muddled outfit for the NPG outing – charcoal trousers, charcoal turtleneck and a shapeless brown blazer. Well, now the blazer’s designer is speaking out – even though Kate doesn’t want to talk about clothes, for the love of god – and saying that Kate is “one of a kind” and more.

Kate Middleton’s style choices are a reflection of her priorities, in more ways than one. When the Princess of Wales wore a minimalist outfit to visit an art gallery on Feb. 4, the look seemed to underscore a recent report that the palace would be focusing less on what she wears and more on her charitable causes. However, the designer of the chocolate brown wool-blend blazer she wore to hang out with kindergarten kids at the National Portrait Gallery recently says that her style directive is so appealing because of its simplicity, not in spite of it.

“I think she looks much more modern in the way she dresses now,” Petar Petrov, the Austrian-based designer tells PEOPLE. “She looks relaxed, and I think she can win the hearts of people even more because she feels like a real person that people can connect with, like Princess Diana. That’s special and makes her even more relevant than ever.”

The designer, whose celebrity clients include Nicole Kidman and Zoe Saldana, says he had no idea that Princess Kate was going to wear the blazer until he saw pictures of her getting off the minibus outside the museum in London.

“We were so surprised when this happened! We don’t know which retailer she bought it from but we are so happy to see she bought it independently and wears it so well,” he says.

The $1,530 jacket sold out within 24 hours. The designer says, “We have had a lot of requests! We are continually trying to restock the blazer. She definitely has an impact, and we have experienced the ‘Kate Effect’ — and we are enjoying it!”

On how the impact differs from his other clients, the designer says, “We are used to working with Hollywood celebrities, but she is not that sort of celebrity, Kate is a very different thing entirely, she is truly one of a kind. She is not a movie star or a top model, she is an amazing addition for us.”

[From People]

I’m sorry, this jacket costs HOW MUCH? $1530 for that?? For some reason, I thought of that Alessandra Rich interview from a few years ago, where she was basically like… sure, I’m glad Kate wears my pieces but people get the wrong impression of my clothes because Kate makes them look so fussy and conservative. I think that’s a consistent designer dilemma – I know people roll their eyes at “The Kate Effect” at this point, but it’s true that Kate can and sometimes does give designers exposure. The problem for those designers is that Kate tends to bring all of her fussy, buttony, doily energy to their pieces. All I’ll say is that seeing Kate in this jacket did not make me want to see what else the designer is doing, you know?

Photos courtesy of Avalon Red, Cover Images, Backgrid.