My stepdad's sister was once in a relationship with Ian Holm, and they're still on good terms, so I met him once. This was around 2002 or so, so when the LOTR movies were big news. I was so anxious, I tried to run away, so if he was left with any impression of me at all, it was probably "crazy person".
Princess Anne visited the CAB where I volunteer a couple of years ago. She was all right, as royals go.
I once saw Peter Stringfellow looking at train times in Victoria Station, but I didn't speak to him. He's quite short.