Queen Mary has quietly returned to Tasmania to attend a private memorial service for her late father John Donaldson.

The Danish monarch and her husband King Frederik X reportedly flew from Copenhagen earlier this week.

The Danish Royal House added a note to their official diary late on Wednesday (AEST), confirming: “The King and Queen attend a private memorial service for the Queen’s father, Mr. John Donaldson, in Hobart, Tasmania”.

Their 20-year-old son, Crown Prince Christian, is acting as regent in their absence.

Queen Mary and King Frederik were in Australia the month before her father’s death for a six-day state visit. At the end of the trip, they spent “precious time” with her father.

When he died in April, Mary posted on Instagram: “My heart is heavy, and my thoughts are grey. My beloved father has passed away.”

“But I know that when the grief settles, the memories will brighten my day, and what will remain strongest is love and gratitude for everything he gave me and taught me.”

At the time it was reported that the family would hold a private memorial service.

Mary’s father, John Donaldson, beamed with pride as he walked his daughter down the aisle.

Donaldson, a professor of applied mathematics, was born in Scotland in 1941 and later moved to Australia in 1963 with his wife, Henrietta. They became Australian citizens in 1975. Henrietta Donaldson died in 1997, seven years before her youngest daughter married the then Danish crown prince.

In 2001, Donald remarried, to a British author named Susan Horwood who writes crime novels under the pen name Susan Moody.

The Danish royal house’s website opened a digital condolence book where people could write messages.

Donaldson wore a kilt and beamed as he gave his daughter away during the church wedding ceremony at Copenhagen Cathedral on May 14, 2004.

-with AAP