Oh, yes! He was to come there with Wickham, you know. But gracious me! I quite forgot! I ought not to have said a word about it. I promised them so faithfully! What will Wickham say? It was to be such a secret!
– Jane Austen
Pride and Prejudice, Chapter 51. Giddy over her marriage to Wickham, Lydia recounts to her family all the details of her wedding, including the revelation that there was one unexpected guest there – Mr. Darcy! She had blurted it out before she realized it was meant to be a secret.