Norway's Crown Princess Mette-Marit makes first public appearance since rare diagnosis announced

Crown Princess Mette-Marit of Norway has been seen in public for the first time since announcing her diagnosis of a rare lung disease earlier in the week.

The mother-of-three joined her family at an annual Parliament Banquet dinner on Thursday, held in Oslo's Royal Palace.

Donning a new black gown with a red sash, the 45-year-old gave a huge smile as she walked through the Palace holding hands with her husband, Crown Prince Haakon.

Just as The Duchess of Cambridge borrows tiara's from the Royal Collection for nights such as these, the Crown Princess donned the stunning Norwegian Amethyst Necklace Tiara.

The blonde beauty added matching earrings and a necklace to complete her look for the formal event.

On the other arm of Crown Prince Haakon was his aunt Princess Astrid, Mrs Ferner, who also sported some crown jewels, as did his mother Queen Sonja.

According to the Royal Family's website the gala dinner features a menu of "food made from Norwegian ingredients, and preferably from the royal properties".

"The tables are decorated by Hoffet's flower decorators, and with silver items, which in their time were gifts to King Haakon and Queen Maud."

On Wednesday the Palace revealed the princess, 45, has been diagnosed with chronic pulmonary fibrosis, a rare lung disease, which may impact her royal duties.

"For a number of years, I have had health challenges on a regular basis, and now we know more about what these are in.

"The condition means that the working capacity will vary. The Crown Prince and I choose to inform you about this now, partly because in future there will be a need to plan periods without an official program. In connection with treatment and when the disease is more active, this will be necessary," the Crown Princess said.

"Although such a diagnosis in times will limit my life, I'm glad that the disease has been discovered so early. My goal is still to work and participate in the official program as much as possible," she added.