Wedding crasher

Not quite. But almost. I'm going to a wedding reception tomorrow and I've met neither the bride or groom before.
Mosh plays fives with the groom and led me to believe that is was some sort of casual do as the actual wedding was a while ago. So I was thinking jeans, free drink, scran, slightly tipsy and doesn't matter too much if you make a bit of a tit of yourself by dancing stupidly at the disco.
Tonight he shows me the invite which looks quite posh and the dress code is suits for the blokes and frocks for the girls. Bloody frocks and it actually said frocks. They have got to be kidding. I don't do frocks.
So it looks like its going to be dressing smart ie like I have to dress for meetings at work, be well-behaved and make polite chit chat with complete strangers.
Hmmm reminds me of something I'd have to attend one evening mid-week :0(