An AAC Beaver was on a VFR transit through the Gloucester ATZ about 10 years ago. I was the Tower Controller and a rather lovely lady ATCO was on Approach. The appropriate co-ordination took place and a few minutes later I spotted the aircraft approaching from the north. I turned to her and said quite innocently 'I can see your Beaver!' Neither of us could speak for laughing for several minutes aftwerwards!