Bradley Walsh says he thought he was “going to prove” that the pyramids in Egypt were built by aliens before investigating the conspiracy theory as part of a new show.

The presenter, 64, known for The Chase and Gladiators, has always been interested in the tomb structures at Giza since he was child as his teacher was the great-niece of Howard Carter, who found Tutankhamun’s tomb.

As part of the Sky History programme Bradley Walsh: Egypt’s Cosmic Code, he travelled to the country after hearing “this rumour that the pyramids weren’t built by Ancient Egyptians at all”, and “they were built by a race that had either died out prior to 4,500 years ago, or they were built by someone or something else”.

Walsh added: “Prior to arriving in Egypt, I’m thinking: this is going be great, I’m going to prove this is the aliens.

“People say I’m a conspiracy theorist. I’m not. All I did was say: ‘It could be this,’ and I needed to find out what is the truth.”

Walsh said that, being there, “you then realise it’s very difficult to take on board that anyone else other than ‘the Ancient Egyptians built the pyramids'”.

“The great thing about the Great Pyramid is they started building the pyramids about 150 years prior to that one,” he said.

“My expert guides showed me where the beginnings of the pyramids were about 150 years prior to the Gre Pyramid. If you went there, you see the evolution of the pyramids – one’s wonky, one’s drooping on one side, it’s all trial and error.”

Walsh also appeared to suggest that being inside the Great Pyramid made him stop believing that it could generate electricity.

He said: “Being so deep inside the pyramid, I was expecting a lot of noise. I’ve maintained that I think the Great Pyramid is some kind of power plant in its own right.”

Walsh also said that it was “mind-blowing being there”, and finding out that the final ruler of Egypt, Cleopatra VII, lover of Mark Antony and Julius Caesar, died closer to the modern era than the beginning of the Ancient Egypt.

He said: “You can go online and get a load of speculative information from people that have never even been there, they’ve got it from a book or somewhere else online, and you know how dangerous the web can be in terms of misinformation.

“Well, if you are interested in the pyramids, hopefully people will watch this and go and see it for themselves. I hope they do because it certainly broadens the mind – it also narrows it, to a certain extent, in that you can see all the real information laid out in front of you.”

The Great Pyramid of Giza was built more than 4,600 years ago to house Khufu, a king from Egypt’s Fouth Dynasty.

Bradley Walsh: Egypt’s Cosmic Code airs on Tuesday, March 18 at 9pm on Sky History