The two worked together on the film "Don't Worry Darling," which is reportedly how they met. Styles stars in the flick while Wilde directs and also appears.
During their romantic vacation, the two were seen sharing a kiss on a boat while a bikini-clad Wilde laid out reading a book.
The actress wore a dark blue two-piece while the "Watermelon Sugar" singer wore black Nike shorts, a dark green top, golden glasses and a blue baseball hat with white lettering.
According to Page Six, the two are currently vacationing at Il Pellicano in Porto Ercole, a five-star resort, on the Argentario Coast of Tuscany.
Styles was spotted enjoying time at the hotel as well, the outlet reports, as Styles was seen taking a dip and relaxing on the hotel’s terraced beach ahead of Wilde's arrival from the UK. She had been across the pond with her two children visiting her ex, Jason Sudeikis.
The exclusive resort only has 29 rooms and suites go for around $3,500 a night.
Page Six says that the hotel has been a hotspot for some of the world's biggest stars and public figures, including Charlie Chaplin, Sophia Loren, Queen Juliana of the Netherlands, Josh Hartnett and more.
"Harry has a strong connection to Tuscany, it is one of his favorite places," a source told the outlet. "He bought a small house there years ago when One Direction first became huge. It is no surprise he has brought Olivia here."
Last week, they visited the Island of Giglio near Tuscany after spending time in the town of Porto Ercole on Monte Argentario.
"Harry has been seen taking a break on the beach in Porto Ercole after he finished filming ‘My Policeman’ in London," a source previously told Page Six.