It's due to start ticking on Thursday (August 12) - during the first week of the holy month of Ramadan - for a three-month trial period.
According to Saudi state news agency SPA, the clock tower's height will reach 601 metres (1,983 feet) and feature a shimmering spire topped by a golden crescent moon on its top section.
Some of its four glimmering 46-metre (151 feet) faces of high-tech composite tiles will be laced with gold, with the Arabic words 'In the Name of Allah' in huge lettering illuminated by two million LED lights underneath.
The clock's faces will be over six times larger in diameter than those of Big Ben, while around 21,000 white and green-coloured lights fitted at the top of the clock will flash as far as 30 kilometres (18.7 miles) five times a day to signal Islam's mandatory prayers.
'Everyone is interested to see the clock, despite the lack of sufficient information about it, and its mechanism,' said Mecca resident Hani al-Wajeeh.
'We in Mecca hope to be the world's central time zone, and not just have a clock to look at, to show off,' he added.
The clock is at the centre of a vast complex, funded by the Saudi government, that also contains hotels, shopping centres and conference halls.
Could Saudi Arabia's clock tower herald the dawn of Mecca mean time? (Pic: EPA)
Watches in Britain have been set to Big Ben since 1880
Read more: http://www.metro.co.uk/news/837745-mecca-clock-to-replace-big-ben-and-gmt-as-centre-of-time#ixzz14lspFEuP