Lego never announces all of its sets at the same time, often leaving little things for special occasions or for people to find out about for themselves. While a whole slew of Lego Harry Potter sets were just released, including that giant Hogwarts, a smaller unannounced set has been spotted out in the wild. It's Diagon Alley.
According to Brickset 40289 Diagon Alley was spotted in a certified Lego store in Solvenia, so it's unlikely to be a fake. It probably got sent out a bit early and put on the shelves by mistake, leaving fans to spot the mystery set and grab some images. Like the giant Hogwarts the Diagon Alley set is microfigure scale, featuring famous shops as they appeared in the film series. That means Weasley's Wizard Wheezes, Gringotts, Olivander's wand shop, Flourish and Blotts (the book shop), and Quality Qudditch supplies. Plus an Olivander minifigure.
All images: Brickset
It's not clear how large this set is, or how many pieces it includes, but it's certainly not a giant playset that's going to take up your entire desk. It's also not one of the dirt-cheap sets you might pick up for £10 from the looks of things. Maybe £20-£30? That's my guess, especially since you have to consider the possible nerd mark-up Lego slaps on themes like Harry Potter.
The good news is that if this has popped up in store, there probably isn't going to be a long wait before it goes on general sale. [Brickset]