mueller diligently prepare for this testimony. i've learned over the past few days, past few weeks mueller has been using unoccupied space at the mueller's previous law firm to prepare for this. robert mueller's spokesperson wouldn't get into the content of it preparation but again reiterated robert mueller will stick to his report. wouldn't give much indication about his demeanor either other than saying robert mueller will be prepared as he always is. of course someone who will be next to robbery muter is his former deputy. and then we understand he will also be sworn in as a witness before the house intelligence committee in that second set of hearings. this is something that the department of justice objects to. it is against department practice to have attorneys in this type of setting sitting next to the special counsel testifying.