Daniel Day-Lewis played the part of a man who had done lechery and felt bad for it. He tried to expose Abigail by admitting to lechery, but his wife didn't want to soil his good name so she denied it. He ended up tearing up his confession
I know who John Proctor is, I said I don't know who PLAYED John Proctor.
What, do you think I'm some kind of idiot?
The way I had said what I said was to mean "You don't know who played John Proctor? It was Daniel Day-Lewis" with the last bit being the description part.