The baths, excavated in a Roman villa, represent "one of the largest private thermal complexes" yet discovered in the ancient city, near Naples, which was devastated when nearby Mount Vesuvius erupted nearly 2,000 years ago.
According to Pompeii's statement, guests shed their clothes in a dressing room that could have held up to 30 people, judging by the benches available.
They would then relax in the 'calidarium', a room with a hot bath, followed by the 'tepidarium' or warm room, and finally they would take a dip in a pool of cold water in the 'frigidarium'.
The cold room in particular was "very impressive", with "a courtyard with a portico measuring 10 metres square, in the centre of which is a large pool", Pompeii said.
Guests then dined by candlelight in a black-walled banquet hall decorated with scenes from Greek mythology.
The hall and spa are part of a grand villa that archaeologists have been uncovering for the past two years.
"The direct connection of the thermal rooms with the large meeting hall suggests that the Roman house was suitable for hosting lavish banquets," Pompeii said in the statement.
These were "valuable opportunities for the owner to secure the electoral consent of his guests, to encourage the candidacy of friends or relatives, or simply to assert his social status," it said.
When Mount Vesuvius erupted in 79 AD, the fallen ash and rock helped preserve many of Pompeii's buildings almost as they were, as well as forming eerie shapes around the shrunken bodies of the disaster's victims.
The remains of more than 1,000 victims have been discovered during excavations at Pompeii, but many more are thought to have perished.
Pompeii is now a UNESCO World Heritage Site and is the second most visited tourist site in Italy after the Colosseum in Rome. | BGNES
