The video has been watched by tens of millions of people all across the globe - and chances are most of them teared up at the now famous sight of Christian the lion reuniting with his original owners.
The story behind this incredible reunion is lesser known though. The website for the book about this incredible lion, A Lion Named Christian, says the lion was bought in 1969 by two traveling Australians who'd arrived in London. The young lion had been rejected by its mother and was sold to the British department store Harrods when Ace Bourke and John Rendall decided to take him in, and treat him as their own.
Christian lived in Chelsea during the swinging sixties where Ace and John worked and lived above an antique furniture store. The Daily Mail says Christian was occasionally touted around town in their Bentley, and posed for photographers - but that he mostly played in the backyard of the antique shop.
The book explains that in those days it was somewhat normal to have exotic pets - and was well before the Endangered Species Act of 1976.
Over the first year though, the big cat got bigger - and soon Ace and John knew they needed a more stable environment for their friend. After just a year together, the two decided to get Christian to Kenya to live with a real pride of lions.
The Kenyan government eventually set aside land north of Nairobi for Christian and other lions to come together in 1970. That's when A Lion Named Christian explains that the story we all know starts to play out.
When Ace and John brought Christian back to Africa, two documentary crews followed them to create the films: The Lion at World's End, and Christian The Lion. It was this footage that sparked the internet sensation we know today - with videos of Christian, Ace and John's reunion clocking in well of 100 million views.
It was 1971 when Ace and John returned to Kenya to see their good friend - who clearly didn't forget them. What's not shown in the video though are the years to come. Eventually, Christian left the man-made pride created for him at the Kenyan sanctuary, and went out into the wild all on his own. Ace and John presume Christian went on to live the life of a real lion - leading his own pride.
As if the video itself wasn't incredible enough, Christian's story is pretty amazing too. Check out the video below that Animal Planet made highlighting this beautiful story.