Will I look ridiculous wearing the dress I bought at the market to a fancy wedding?

Hey girls, I have a question. Next week my close friend's wedding is happening, but my budget is really tight right now, so I couldn't buy anything from those brands. The other day I found a dress at the market that is literally a copy of a famous brand, but the fabric seems a bit thin, and it really shows off my body shape; I mean, I do have a bit of a belly, to be honest. Do you think people would realize it's cheap, or would I stick out too much in that setting? I really have no idea, so please give me some advice; I'm very undecided.