Is John Green ever going to write "An Imperial Affliction"?

So when I first read TFiOS, I looked up "An Imperial Affliction" to find out if it's a real book, and I was so disappointed to find out that it wasn't. From what Hazel said about it, it looks really good!! Does anyone know if John Green is planning to actually write it? I haven't heard anything about it becoming a real book, but I would definitely read it.