Norway's Crown Princess Mette-Marit has completed a successful lung transplant in Oslo, according to an announcement from the royal household.

The 52-year-old was first diagnosed with pulmonary fibrosis in 2018, though her condition had grown markedly worse over recent months.

"We are delighted that everything has progressed well so far," said lung specialist Are Holm in the palace statement.

He noted that Mette-Marit will stay under hospital observation for several weeks, which is standard following any transplant.

Prince Haakon intends to adapt his schedule to provide support during her recovery period.

The transplant represents welcome news for the Norwegian royal family and the country as a whole, according to historian and commentator Ole-Jørgen Schulsrud-Hansen.

"This overcomes one of the most serious hurdles toward better health for the Crown Princess, and many people feel relieved at the positive outcome," he added.

Mette-Marit married Haakon in 2001 and has managed a rare form of pulmonary fibrosis that leads to ongoing breathing difficulties.

With her health declining she reduced public duties, and specialists had earlier described the deterioration as significant and dangerous.

She last appeared publicly on 17 May, by which time she required a nasal tube linked to an oxygen supply.

The palace confirmed she joined the transplant list 12 days ago, noting that those listed are generally considered to have roughly one year to live without intervention.

"We always prioritise the sickest," Holm stated.

He also underlined that post-transplant recovery demands lifelong immunosuppressive medication and careful monitoring.

One in eight recipients do not survive the first year, while roughly half remain alive after ten years.

The operation follows a challenging period for the royals, including January disclosures about Mette-Marit's past contact with Jeffrey Epstein.

She later apologised to the king and queen, acknowledging poor judgement and stating publicly that she wished she had never met him.