Egypt has invited the famed and eccentric billionaire technology guru Elon Musk to visit the pyramids, so he can see for himself that they were not built by aliens.

The invitation followed Musk, who heads up the United States electric vehicle and clean-energy company Tesla, writing on Twitter that the massive ancient monuments must surely have been made by aliens.

His five-word apparent endorsement of the well-known conspiracy theory said simply: "Aliens built the pyramids obv."

Musk, who also runs the aerospace manufacturer SpaceX, immediately heard back from Egypt's minister of international cooperation, Rania al-Mashat, who tweeted that, while she admired Musk's work at SpaceX, he was wrong to think the pyramids had an extraterrestrial builder. She added that he would be welcome to visit and see for himself how humans created the engineering marvels.

She concluded by saying: "Mr. Musk, we are waiting for you."

Prominent Egyptian archaeologist Zahi Hawass appeared to have been even less impressed with Musk's comments and posted a short video in Arabic that Egypt Today said describes the idea of the pyramids having been built by aliens as "complete hallucination".

"I found the tombs of the pyramids' builders, which tell everyone that the builders of the pyramids are Egyptians," the paper quoted him as saying, in reference to burial sites he uncovered in the 1990s of the ancient Egyptians who built the towering structures.

The Daily Mail noted that archaeologists added new details in 2018 to their understanding of how humans managed to build the massive stone tombs when they discovered a pyramid built 4,500 years ago by the Fourth Dynasty pharaoh Khufu employed a ramp system at an ancient quarry in the Eastern Desert. The ramps made it possible for people to drag massive alabaster stones up a slope with the help of sleds and rope.

Musk seemed to step back from his earlier comment in a later tweet in which he shared a link to a BBC History site that offers a historical account of the humans who built the pyramids. He said: "This BBC article provides a sensible summary for how it was done."

Musk is well known for posting social media messages that are capable of incensing some people and that can at times appear to be poorly thought-out.

On Jan 31, he likened COVID-19 to the common cold and said "the coronavirus panic is dumb".

And during an appearance on a podcast hosted by comedian Joe Rogan in 2018, he appeared to smoke marijuana while claiming humans could be living in a fake reality similar to the one described in the 1999 movie The Matrix.