Celebrity etiquette?

What would you do if you found yourself sat on a train next to someone you are 99.9% certain is him (or her) off the telly?  Would you try to engage them in conversation, or would you treat them the same as any other passenger (which usually means avoiding eye contact and only speaking if there is absolutely no alternative)?

I found myself in this position on a packed 18:05 from Euston last Thursday.  A man I recognised as a TV comedian and panel game participant got on the train at Euston. 

The celebrity didn't look very happy, but then no one does when they are stuck between two other adult men on a bench of three seats.  No room to move, no room to sit back.  He stayed, rigidly sat upright until we got to Watford where he got off.

This has happened to me twice before.  On an overground train out of Liverpool Street I found myself sat opposite the recent winner of one of the BBC Apprentice series (presumably off to Lord Sugar's HQ in north east London) and then there was an occasion when I found myself walking along an almost empty London Underground platform past the (then) England cricket captain.

I reckon that the first two were probably grateful that no one acknowledged who they were (on the Thursday's 18:05 there was no room for autographs) but the cricketer did look like he was hoping someone would speak (if he was then he was disappointed!)

Has this happened to you to, and if so what did you do?  If you spoke to them then how did they react?  Did they seem pleased to get the attention, or were they annoyed?



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