In the video, numerous excavators can be seen digging a wide linear trench in the desert. Within the trench, foundations for the city, which is planned to be 170 kilometres long, are expected to be built.
The works could also show preparation for an underground transport system that is planned to be built underneath the length of the city.
Unveiled earlier this year, The Line has been designed to house nine million people. It will be 500 metres tall and have a mirrored facade.
Following its announcement, numerous people were unconvinced that the project would be realised, with one Dezeen commenter stating: "If this gets built I will eat everybody's hat".
However, the footage suggests that work on the city is now underway.
Speaking to Dezeen in an exclusive interview, Neom's executive director for urban planning Tarek Qaddumi said that The Line megacity will "revolutionise our current way of life" and will be net-zero over its lifetime.
However, experts refuted the project's sustainability and liveability claims.
The megacity is part of the controversial Neom project that will see 10 regions developed in the northwest of the country. Alongside The Line, which is being designed by US studio Morphosis, a ski resort designed by Zaha Hadid Architects, UNStudio, Aedas, LAVA and Bureau Proberts is planned.
Earlier this week human rights organisation ALQST reported that three men who had been forcibly evicted from the Neom site had been sentenced to death.