How can I stop talking in my sleep?

I want to stop talking in my sleep, I never say anything wrong or evil or bad but I find it embarrassing. My fiance tells me that I talk in my sleep a lot and say very random or stupid things, it's not a problem I suppose but I find it embarrassing that I have no control over what I am saying nor do I remember it in the morning. In fact unless she told me about it, chances are that I wouldn't even know I had done it. Is there any way to stop talking in your sleep or is this just something I'm going to have to live with?