Camilla, Duchess of Cornwall has been borrowing from Prince Charles's wardrobe, it seems.
To appear on stage at the Platinum Party at the Palace, the jubilee concert, she wore a midnight blue robe, or daqlah, which was first given to her husband on a visit to Saudi Arabia in the 1990s.
The piece, which is dark blue with silver embroidery, is designed to be worn over a thobe.
It was created by Saudi designer Yahya Al Bishri and is a wool and cashmere blend.
A daqlah is a "garment worn by the rich and powerful". It is a long robe that is open in the front and closed at the neck opening with buttons.
Prince Charles was seen wearing the piece in Saudi Arabia after it was presented to him. The date he was given the piece has not been confirmed.
For the platinum jubilee event, the Duchess of Cornwall wore it as a floor-length dress. When she arrived, she covered the intricate piece with a lightweight navy jacket.
In recent years, the duchess has started to make a style name for herself.
Often dressed by designer Fiona Clare, tartan and tweed coats, to protect her from the brisk British weather, are favourites of Camilla's.
She has also sported relaxed floral dresses for daytime commitments.
Over Queen Elizabeth II's platinum jubilee weekend, she wore a ribboned blue coat dress to attend the Trooping the Colour parade, and an embellished brush silk coat dress with a wide-brimmed white hat for the thanksgiving service.
On the final day, to watch the jubilee pageant and make a balcony appearance with fellow royals at Buckingham Palace, she wore a white coat dress with navy blue detail.
Anna Valentine is another favourite designer of the royal.
Not only did Valentine design the two outfits for her 2005 wedding to Prince Charles, but the designer is also behind the all-white flowing trouser and top ensemble she wore on during her November visit to Jordan.
No stranger to a hat, Camilla often chooses to top her outfits with a little millinery, opting for larger-than-life designs, often by Philip Treacy, for formal events.