on the edge of your seat
on the edge of (one's) seat
Excited, nervous, or filled with suspense while one waits to find out what happens next. Often said of those viewing a movie or TV show. The image is that of one literally sitting on the front of their chair because they are unable to sit back and relax. It's not going to win any awards, but the film certainly kept us on the edge of our seat from start to finish. I've been on the edge of my seat waiting for my acceptance letter.