Disclosing your stutter before your interview is one of the most important things a stutterer can do to improve their chances of getting the job. Usually, when I am emailed an invitation to interview, I'll just include a 'oh by the way, I have a bit of a stutter that gets worse when nervous so please let the interviewer know that it's me, not him." or something like that. And on the other side, I used to be the interviewer, hiring many people over the years. It's my job to get the most out of a candidate, so we can be sure to hire the right person. If a candidate is paralysed with fear, or has some other stress issues, I'm not doing my job to relax them, so they can shine. Don't forget, employers want to hire the best people and everyone knows interviews are stressful. I always appreciated when interviewees told me or HR about whatever issue they have. It's really no problem at all. I would just spend the first few minutes making small talk about the weather and what not until they get a bit more relaxed and then slowly ease into the interview. You'll be doing yourself and the interviewer a big favour by letting them know you stutter.