This seems to happen. For example, I met Adam from the GLC the other day (before their gig) and it was a really weird, stunted conversation as I was a little bit taken about the whole situation.
I'm fully aware that GLC members might not be the calibre of celebrity you were hoping for so here's this story: My mate was in a band touring in LA and went on some show where he met Bruce Willis. He was reading earlier that Bruce Willis was going to do Die Hard 4 in some in-house mag (this was before it was made, obvs).
So when he met him, he said "oh I heard you're doing Die Hard 4" and Bruce Willis said "no I'm not" and he said "oh, because the industry papers say you are" and Bruce Willis just started at him and walked off.
Got any more?