Quite a few...
My wife once sat in the same Tube carriage as Super Hans out of Peep Show. It was on the Northern line and he had skull-patterned socks on. She got on at Archway and he was already in the carriage.

She also once followed Daniel Day Lewis down the street in New York. He went into a deli.

We saw Vic Reeves in the Sainsbury's Local at Manchester Piccadilly station, a few months ago. He had a white beard.

I once stood behind the actor Jason Merrells at Leeds railway station M&S. A few weeks before that, at the same station, I got out of a taxi just as Neil Pearson was getting out of the one in front.

Last year, I sat in a first class carriage on the St Pancras to Sheffield train and Melvyn Bragg was in the seat on the other side of the aisle. He's in remarkably good nick for a chap in his early seventies. Brilliant hair.

I once walked past Noel Gallagher on Deansgate in Manchester. He's tiny.
(Dinting Arches, Sat 22 Sep 2012, 22:08, Reply)