October 20th Games Workshop will be celebrating Warhammer after opening up their 500th worldwide store. There will be two new models, one from AoS and the other for Warhammer 40,000. No details yet on what it will be, but it will be available at any of the Games Workshop stores that you can get to.
Here is additional info on the event and GW's celebration for 500 worldwide stores.
"we’re releasing not one but TWO exclusive miniatures on celebration day. We’ll have more news on these soon, but for now, we can confirm that one will hail from the Mortal Realms, and the other from the 41st Millennium…"