The Church of Norway says in a press release that intercessory prayers are often held for the royal family, but that on Sunday there will be special prayers for the Crown Princess.
In the Church of Norway we will pray for her and those close to her on Sunday, says leading bishop Olav Fykse Tveit.
When someone in the royal family is seriously ill, it is natural that we include this specifically in our prayers, he says.
Crown Princess Mette-Marit has had pulmonary fibrosis for several years. Recently, both King Harald and Crown Prince Haakon have said that her condition has worsened.
On Thursday, Crown Prince Haakon landed in Norway after cutting short his official visit to Japan. Princess Ingrid Alexandra has also arrived in Norway from studies in Australia.
The Crown Prince has said that Mette-Marit's illness is the reason the family is now gathering in Norway.
The Crown Princess has appeared in public several times in recent months on a ventilator. In December, it was announced that she was being prepared for a possible lung transplant. Such operations are considered for people who have a life expectancy of one to two years without a transplant.
