In 1969, John Rendall and Ace Berg, bought a lion cub at Harrods. They gave him more space, brought it tame, then decided to free him in Africa (he was getting much too large for their flat!) A year later, they heard that he was the head of his own pride. Despite the near-impossibility that the lion could remember them, they decided to pay him a visit. And, was it a good surprise!
He even introduced them to one of his females!