An 18-carat gold bathtub weighing 154.2 kilograms at a Japanese hot spring resort has been recognized by Guinness World Records as the heaviest on the planet, the resort's operator said.

The tub worth ¥800 million measures 1.3 meters in diameter, large enough to allow two adults to relax, Huis Ten Bosch Co. said Monday.

"This gold bathtub outclasses all others in the world, and we hope our customers enjoy it and increase their luck," the company said.

The tub was made by Tokyo goldsmiths while the resort's hot spring facility was undergoing a renovation.

The tub, which Guinness confirmed to work properly for practical use, is located in a reserved space and can be used by up to four people for ¥5,400 per hour.

The resort, known for its salty, brown-colored spring water, has various themed baths and reserved private baths.