He weighs around 500lb and has a face only his mother would love.

But Ambam the gorilla has become an overnight internet sensation - viewed across the world almost five million times.

Ambam, a 20-year-old Silverback Western lowland gorilla, wowed the world by walking upright like a human at Port Lympne.

The clip quickly went viral, thrusting Ambam into global superstardom and news crews from around the world flooded to the park near Folkestone to see Ambam stroll around his enclosure.

Head gorilla keeper, Phil Ridges, said: "We were totally unprepared for the response as Ambam has been exhibiting this behaviour his whole life. Just days after uploading the clip the phones were ringing off the hook with people wanting to know about Ambam and we were inundated with requests from around the world for interviews and information.

"We have had a lot of speculation that it is a man in a gorilla suit or that he has been trained to do this but Ambam has not been trained in any way, it is just something he chooses and is able to do."

The footage was filmed by animal researcher Johanna Watson whilst she was working with the University of Manchester for a project on great ape locomotion.

Mr Ridges added: "There have certainly been more people coming down to see the gorillas at feeding time and looking out for him to stand up, but Ambam doesn't seem to know what the fuss is all about.

"All gorillas can do it to some extent but we haven't got any who do it like Ambam and he is quite a celebrity at the park. We think he might use it to get a height advantage to look over the wall when keepers come to feed him and standing up can also help him in looking for food generally in his enclosure as it gives him a better vantage point.

"Ambam can also carry a lot more food if he stands and uses both hands and walking on two feet also means he doesn't get his hands wet when it is raining."

Visitors to Port Lympne can see Ambam and the rest of his group being scatter fed daily at noon and 3pm.

To view the clip of Ambam visit Port Lympne's site

For further information on visiting the gorillas at Port Lympne or to adopt a gorilla from £3 per month go to the Aspinall Foundation website.