This happened years ago at the Crewe & Nantwich Folk Festival:

Very Posh Nantwich Lady: Are you well known? I seem to have seen you before somewhere...

Me: Well, I have been on at the Festival before, and I've been at Middlewich Festival doing...

VPNL: No, no....wait! I've got it! You look just like one of the workmen who redecorated my drawing room!