I used to work in Fulham, and would sometimes see Leslie Grantham (Dirty Den from EE) queuing up in the NatWest Bank - this was in the days of proper banks with wooden counters and human cashiers.
He looked, and dressed, exactly the same as his character, and was quite happy to chat with anyone.
He stood in a queue behind me in M&S, he was very nice, chatty. Though I didn't talk to him about the fact he is famous..It was at a time when he was back in Eastenders too.
Also Pierce Bronson, have seen him at Mass in a London parish, very nice despite being recognised by children that where saying "Mummy, mummy it's James Bond."
Katherine, Duchess of Windsor and her daughter, stood behind them in a queue for ice cream at Wimbledon, didn't speak to them but they happily blended with the crowds, no bodyguards or security or staff.#
Alistair Stewart smiled and said hello when he walked pasted me.