The newly-crowned world's largest yacht took the seas yesterday - a £400million (€462m) behemoth which is a staggering 590ft long.
The yacht, called 'Azzam', was built by a German firm and has beaten Roman Abramovich's 533ft 'Eclipse' to the top spot.
Azzam was officially unveiled in April, but was seen by 'yachtspotters' being tested on the North Sea at the weekend.
The megayacht is believed to have been ordered by a Middle-Eastern billionaire.
It can travel in excess of 30 knots with power coming from a combination of two gas turbines and two diesel engines with a total of 94,000 horsepower.
Peter Seyfferth, from TheYachtPhoto.com, said: 'During the three days of trials, Azzam reached an amazing top speed of 31.5 knots, making her not only the longest but also by far the fastest megayacht in the world.
'Such a speed is absolutely exceptional for a yacht of this size.
'Her elegant, sleek lines are another feature which distinguish Azzam from all the other yachts above 150 metres.'
Azzam, which took three years to make, boasts 94,000 horsepower, thanks to a combination of two gas turbines and two diesel engines.
Mubarak Saad al Ahbabi was the engineer behind the megayacht, assembling a team to work on the ultra-sophisticated project.
He was told by the yacht’s secret buyer to built a vessel which was innovative and had a timeless design which would be able to travel at high speed and in shallow waters.
The exterior design, which has been described as 'surprisingly slender' was carried out by Nauta Yachts with interior designer Christophe Leoni working on Azzam’s inside.
Azzam is expected to be delivered to its owner later this year.