Well, you could have knocked me over with a feather.
4 seconds sound clip from the Meet John Doe (1941) movie soundboard.
You can hear this line at 01:01:10 in the DVD version of the movie.
Quote context
[...]
- I turned round to my wife and she said:
- So in a voice you could've heard in the next county I said:
- Well, you could have knocked me over with a feather.
- I've been wanting to talk for years only I thought you didn't like me.
- Then he started chatting away like a happy little kid. Got so excited his eyes...
- He says it's a shame how little we know about our neighbors.
[...]