How do you convince a Spanish supermodel with an idyllic summer home on Formentera—an island paradise just 30 minutes by boat from Ibiza—to acquire another summer retreat on the edge of Portugal's agricultural heartland? It took three years, but globe-trotting Argentine interior designer Luis Galliussi got the job done.

"About six years ago, Luis, my best friend and the decorator of my homes in Extremadura and Formentera, and now godfather to my son, Alfonsito, started talking to me about Comporta," says Eugenia Silva, who has been a favorite runway model for Oscar de la Renta, Carolina Herrera, and Giorgio Armani while also becoming a film producer, blogger, and online retail entrepreneur. Her boyfriend—and Alfonsito's father—is Alfonso de Borbón, a prominent businessman and relative of the Spanish royal family, so the couple are not unfamiliar faces in European society pages.

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Silva in her kitchen; the table came from an Ibiza flea market, the stool and pendant light are by IKEA, and the handmade vintage rug is Argentine. 

Located about an hour south of Lisbon on the Alentejan coast of Portugal, Comporta is similar to the Hamptons in that it is a collection of several small villages with a seafaring and agricultural past, all spread along a stretch of spectacular Atlantic coastline. For much of the 19th and 20th centuries, Comporta was a place from which hardscrabble residents fled to seek opportunity elsewhere, leaving behind oceanfront pastures and farmland that can often appear virtually untouched by man.

But unlike in the Hamptons, even after Comporta was rediscovered in the later 20th century, new construction was strictly limited, preserving the area's remote and rustic character. This enforced simplicity has drawn a growing cadre of international artists, designers, and jet-setters—Mario Testino, Christian Louboutin, and Princess Caroline, among them—who come to the far-west corner of Europe in summer to unwind and disappear amid Comporta's secluded coves and pine forests.

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The sink in the master bath was made locally, the fittings are by Grohe, the mirror is by Ikea, and the floor is poured concrete.

"For such a hyper-chic crowd," Galliussi points out, "the true luxury is getting to go everywhere barefoot, and stopping for drinks after the beach without going home first to do yourself up."

Finally, Silva was intrigued enough to pay a visit. "Of course, Luis was right," she recalls. "It felt like this incredible discovery, a refuge of peace, with the dunes and ocean on one side and forests and rice fields on the other."

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On the terrace of model Eugenia Silva's Comporta, Portugal, retreat, which was decorated by Argentine designer Luis Galliussi, African textiles found in Ibiza line the banquette, the urn was found in a nearby village, the floor cushions are covered in the remnants of antique Moroccan kills, and the rug is Moroccan. 

Enchanted by what she describes as "adorable little farmhouses with their thatched roofs, the easy charm of the Portuguese locals, and the cosmopolitan mix of the summer residents," Silva wanted in. But zoning restrictions mean you essentially need one of those "adorable little farmhouses" to get started. With so many of Europe's style mavens and creative types already summering there, wannabe homeowners can search for years before finding a suitable property.

Happily, a friend—Ana Ressano, an interior designer with whom Galliussi shares a studio in Lisbon (he has others in New York, Madrid, and Buenos Aires)—had a large home in the area and offered to renovate three small, abandoned houses overlooking a rice field at the edge of her property. 

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In the master bedroom, the vintage linens belonged to Silva's parents, the suzani was bought in Turkey, the pendant light is by Ikea, and the pine console was made locally.

With Galliussi in charge of the decoration, Ressano's renovation focused on restoring and respecting the humble nature of the rustic buildings. The floors are poured concrete or laid with vintage tiles, the wooden beams and planks came from local trees, and the thatch on the roofs is harvested from nearby riverbanks. Untreated wooden walls in the bathrooms mean each shower brings a fragrant reminder of the adjacent forests.

The three houses now work as one home, with outdoor "living rooms," terraces, and pergolas linking the separate interiors. Adding up to about 1,750 square feet, the place has three bedrooms and baths, a living room with a fireplace, and a kitchen and dining room. Galliussi deployed his characteristically deft high-low blend of furnishings, with custom-made daybeds, an Ikea bench, a turquoise-and-yellow table customized by artist Janis Dellarte, and even an abandoned chair from the property in the mix.

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A rattan cushion by Ikea and an antique Argentine rug on the deck.

"Since everything in summer happens outside," Galliussi says, "we created the terraces to blend into the dunes on which the house sits, so it feels even more integrated with nature."

The striking textiles indoors and out include traditional Portuguese fabrics bought from local village markets and carpets Galliussi commissioned from weavers in Morocco. Other pieces, such as the Bulgarian crocheted bedspreads in the guest room and the woven rug from Catamarca in northern Argentina, were scooped up on his travels.

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The beds in a guest room are topped with crocheted-cotton coverlets from Bulgaria, the wall hanging is Portuguese, and the tile floor is original to the house.

Silva is delighted. "We use different parts of the house at different times of the day, but my favorite is breakfast on the terrace beneath the pergola, facing the rice paddies," she says. "I'm an early riser, so I see our friends emerge from the houses one by one. A neighbor might drop in with fresh bread or an invitation for drinks or dinner, and then it's off to the beach for the day.

"This house—like Comporta, and summer itself—is so easy, chic, and simple," Silva continues. "Nothing gets in the way of relaxing and having fun."