Norway's royal court on Tuesday announced the engagement of Princess Martha Louise to her US boyfriend Durek Verrett, a self-professed shaman and guru to celebrities such as Gwyneth Paltrow.

Fourth in the order of succession behind her brother Prince Haakon and his children, Princess Martha Louise, 50, has previously relinquished most of her official titles and duties in order to devote herself to her private activities. 

"His Majesty the King and Her Majesty the Queen send their most heartfelt congratulations and wish them all the best in the future," the Royal House of Norway said in a statement.

Martha Louise has three daughters from a previous marriage to Norwegian author Ari Behn, who committed suicide in December 2019. The couple had divorced in 2016.

The princess confirmed her relationship to Verrett, 47, also known as Shaman Durek, in 2019.

Martha Louise has been an enthusiast of "alternative therapies" and has an eccentric image in Scandinavia, claiming to communicate with angels, a gift she tries to share through courses and books.

Verrett, who is based in California, has become known as a celebrity shaman, serving as a guru to likes of Paltrow, the Oscar-winning actress turned businesswoman, who founded the lifestyle brand, Goop.

Verrett also confirmed the engagement on social media.

"She said YES!" Verrett said in a post to Instagram.

The couple's relationship has been scrutinised in the Norwegian media, and the princess was criticised for mixing business and royal affairs when she promoted a speaking tour called "The Princess and the Shaman".