Not quite the words that came to mind, but this is exactly what came to my mind.I agree with Saxmanjack. You are worrying too much over a one-off gig. Just enjoy being a sideman for a night and do your best. The "name brand" guy is probably mostly interested in the rhythm section to back him up not sax. He probably doesn't really care what you are playing as long as you aren't stepping all over him. Play minimally to accompany him and don't try for the attention you usually get. Just be friendly. Network with the big shot a little. The experience could help your musical career. If he is really good you might absorb something artistic from the experience also. Have fun rather than being miserable.