From the Ediburgh Scotsman, April 3rd, 1931 (reprinted in Syd Chaplin: A Biography by Lisa K. Stein):
Chaplin found out today that it was April 1. He lunched with his brother Sydney and a large number of friends at a hotel, and one item on the menu was Charlie's favourite dish, "crepes suzette," the fascinating little rolled pancakes which are served with blazing rum. When the dish arrived Charlie took three, and began to tell everyone of the excellent pancakes he had eaten in all four corners of the world. "Ah!" said his brother Sydney, "just eat these, Charlie; I'll bet you've never tasted any like them." Charlie struggled with them for some time before he discovered that they were made of cheesecloth covered with batter. It then gradually dawned on him that he had forgotten the date. "These are too hard on a man," he said, and then joined heartily in the laughter until he was otherwise occupied with some real "crepes suzette."