How do I move iTunes Library to a new drive without losing the 'Date added' field?

How do I move iTunes Library to a new drive without losing the 'Date added' field?

I've run out of drive space on my external and got a new one to move everything on to. I can't afford to lose my 'date added' values. How is this done? I should mention I let iTunes manage the files for me (in other words - it all lives in one place).