A British lad was given the shock of his life after opening a 21st birthday card - which revealed he'd unknowingly been on the receiving end of a family joke for the past three years. Sarah Austin shared the hilarious footage of her son Charlie's big day to TikTok , which has since gone viral at his expense. The clip begins with the birthday boy opening a giant card from his parents, who asked him to "read it out". "Happy 21st birthday, Charlie," he duly responded, oblivious to what is to come.