The luxury private vessel 'Azzam' - with a beam 68-feet high - overshadows previous longest superyacht, The Eclipse, by 57-feet.
Designed by Nauta Yachts in Italy and constructed by German company Lurssen Yachts, Azzam is almost two football fields long and rivals the size of some cruise ships.
It took four years to complete the superyacht from concept to construction,'New York Daily News' reported.
Though the person who commissioned the project still remains a mystery, reports speculate the owner may be a member of the Saudi royal family.
With 94,000 horsepower generated from two gas turbines and two diesel engines, the Azzam can reach speeds of over 55.5kph, which makes it one of the fastest yachts in the world.
The superyacht will require a 50-person crew to maintain and its further specifications are not known yet.
"When she will be delivered later this year, she will have been in build for only three years following one year of engineering," said Peter Lurssen, managing partner of Lurssen Yachts.
"She truly represents another milestone in not only our history but yachting history as well," Lurssen said.