I know the interview may have happened already, but here are my thoughts: if there is a time set for the interview (I work for the government and we actually time interviews and end them after a certain amount of time), you could ask for extra time to complete it. You could ask for the questions at the beginning of the interview, or a chance to collect your thoughts before each question? Although that might either be standard, or giving an advantage you don't need (just brainstorming here). You can also just let him know that you are telling him so he doesn't get caught off guard, but that you are used to stuttering and it doesn't mean you aren't prepared for the interview, or excited about the job. If it's true, you could let him know that you tend to stutter more in interviews than day to day job situations (not that it matters, but I think there is so much people don't know about stuttering and some people don't realize how much fluency can differ). Good luck!