Recently Marvel has been teasing the public with several Fantastic Four related images. The most recent image however shows an old character back with the FF crew. The latest teaser image shows Johnny Storm back on what looks to be a cover for Fantastic Four #600 along with Mr. Fantastic, The Invisible Woman, Spider-Man, and the Thing. As Stephen Schleicher states in his article, the latest teaser image is labeled 4 of 5 so it seems we might get the final reveal tomorrow.
Source – Major Spoilers