Stuttering?

My 3 year old son recently started stuttering. He started while he was at his dads house, I didn’t notice it before. Now it’s happening all the time, almost like he’s doing it on purpose. I feel like he did it a few times, they made a big deal about it and now he’s doing it because it made a reaction. He was talking perfectly in full sentences before, he has since he was 2 and has never had a problem with stuttering until now. Has anyone had any experience with children stuttering?