Cheung made the comments during the celebration ceremony of the 50th Anniversary of the Big Mac, where the company also unveiled a set of collectable coins known as MacCoins to celebrate the Big Mac's birthday.

Steve Easterbrook, McDonald's global CEO, said: "The MacCoin is the first food-backed collectable currency and transcends a single currency to commemorate our global iconic burger, while giving customers all over the world a chance to enjoy a Big Mac on us.