Princess Gabriella of Monaco matches her mother Charlene in tan coat and shades (while brother Jacques, 9, twins with dad Albert)

Princess Gabriella twinned with her mother, Princess Charlene of Monaco, as they stepped out in coordinated winter looks earlier today.

Meanwhile, the nine-year-old royal’s twin brother Jacques matched his father Prince Albert II as the family made a rare joint appearance on Wednesday.

The 66-year-old monarch was accompanied by his wife and two children as they inaugurated a Mareterra – a $2 billion luxury ‘eco-district’ built on land reclaimed from the Mediterranean Sea.

Charlene, 46, and Gabriella both wore matching tan coats over their outfits, providing a striking look at the mother-daughter duo.

The mother-of-two looked chic in her monochrome ensemble, complete with a pair of dark brown kitten heels.

However, her mini-me opted for a black dress and completed her winter outfit with tights and black ballerinas.

On the other hand, Jacques adopted the style cues of his father Albert, who was dressed in navy blue trousers, a light blue shirt and a tie in the same shades.

The heir to the throne of Monaco followed suit and wore an exact replica of his father’s outfit.

The royal family stepped out together to inaugurate the Mareterra district – 11 years after the prestige project was first announced.

According to CNN, the luxury condominium built on top of the sea includes more than 100 apartments and 10 palatial villas – as well as a marina and a promenade.

Influential architects such as Norman Foster and Tadao Ando were reportedly recruited to create structures in Mareterra – with Renzo Piano (best known for the Center Pompidou) even agreeing to lend his name to the residential development designed by his firm.

Although house prices have not been made public, property group Knight Frank reportedly estimates that properties in Mareterra will cost around £82,842.50 (€100,000) per square meter – almost twice as much as the average in Monaco.

Ahead of the inauguration, Prince Albert told Hello Monaco: “I wanted this new area to embody the excellence and conviviality that distinguishes the Principality of Monaco.

‘Mareterra will integrate perfectly with our coastline and will be seen as a natural extension of our territory.’

It appeared that some structures in Mareterra are dedicated to members of the royal family, including a 20 by 20 meter saltwater pool dedicated to former swimming champion Princess Charlene.

The royal family’s latest public engagement comes a day after Princess Charlene and Prince Albert released their family Christmas card.

Dressed in winter sweaters and huddled next to a beautifully decorated Christmas tree, the smiling Monegasque monarchs, along with their nine-year-old twins, Princess Gabriella and Prince Jacques, appear relaxed and happy on screen.

Princess Charlene looked typically elegant in brown straight-leg trousers and a chunky knit turtleneck in a complementary shade.

The former Olympic swimmer paired her outfit with brown leather boots with high heels and pointed toes.

With her blonde hair in a relaxed updo and natural makeup, Charlene, who is usually seen in glamorous ensembles by high-end designers, showed a more casual and homely side of herself in the new photo.

Prince Albert, who at 66 is twenty years older than Charlene, looked equally cozy in a cream-colored cable knit sweater – and the couple’s twins were also dressed in matching outfits.

Gabriella wore a white outfit consisting of pants and a knit, along with a pair of metallic ballet shoes, while grinning Jacques looked cute in black pants and an oatmeal-colored sweater paired with brown suede shoes.

Seated in front of a stone fireplace decorated with festive greenery and lit candles in one of the living rooms of the Princier Palace, the family looked picture-perfect in the photo taken by Eric Mathon, the royal family’s official photographer.

The photo, posted on the official Instagram account of the Royal Family of Monaco, was captioned: “The Princier Palace is pleased to share with you the photo of the Princier family greeting card.”

It has proven to be a huge hit with international royal viewers, racking up more than 12,000 likes and hundreds of enthusiastic comments in less than 24 hours.

One person commented: ‘Beautiful family photo. The choice of clothes. The children are so big and beautiful!’

Another adoring fan from Norway wrote: ‘Aww.. so beautiful. Kind regards and very best wishes for beautiful days before Christmas. Kind regards, me and my twins and family in Norway!’

A third person said: ‘What a cute card! I hope I get it!’

While a fourth commented: ‘Beautiful image of the Princier family, beautiful and happy. MERRY CHRISTMAS.’

A fifth agreed: ‘Beautiful family.’

The relaxed image is in stark contrast to the more formal photos of Princess Charlene and Prince Albert from National Monaco Day, which took place two weeks ago on Tuesday, November 19.