The bizarre tweet has also prompted a response from a top official in Egypt, who invited Mr Musk to visit the country.
Rania Al-Mashat, Egypt’s Minister of International Cooperation, said: “I invite you and SpaceX to explore the writings about how pyramids were built and also to check out the tombs of the pyramid builders.”
Since Mr Musk’s original tweet was published, UFO researcher Scott C Waring has explained why he believes the pyramids could have been built by aliens.
The Great Pyramids of Giza or the Great Pyramids of Khufu have long been a source of mystery and wonder for conspiracy theorists and historians alike.
Raised nearly 5,000 years ago on the sandy plains of Giza, outside modern-day Cairo, the tallest of the three pyramids stands about 456ft-tall (139m).