According to some inside sources of the Nerdist, the new Fantastic 4 have been cast. Miles Teller will be Mr. Fantastic aka Reed Richards, Kate Mara as Invisible Woman aka Sue Storm, and Jamie Bell as the Thing aka Ben Grimm, & Michael B. Jordan as Human Torch. The report says that sources close to the project have confirmed all of these.
Though Jamie Bell has not yet received an official offer, he is expected to play the Thing. There is also some mention of Miles Teller having some scheduling conflicts with the Divergent sequel Insurgent. If Fox can’t workout out the scheduling issues with Teller, then it’s more than likely that they would have to find another actor to do all of the stretching.