Queen Mary was forced to cancel a number of public engagements this week after falling ill.
The Danish queen, 53, had been due to attend an event with the Mary Foundation at the University of Copenhagen on Friday, however this was cancelled.
It comes after Mary was also unable to attend the Heart Association's awards ceremony at the Hotel d'Angleterre in the Danish capital on Wednesday.
In a statement to Danish publication, BT, the Royal House's Communications Department said: "Her Majesty the Queen, like many others right now, has become ill, and therefore unfortunately cannot participate in the Heart Association's award ceremony."
The palace gave no further details about Mary's illness, who usually enjoys good health, but she expressed her gratitude for the get well card and flowers sent to her by twins, Alma and Ellen, who she was due to meet at the Heart Association awards.
"Thank you for the thoughtfulness. What a lovely surprise to receive this bouquet and drawings, even though illness prevented me from participating in the Heart Association's event," she wrote in an Instagram post.
"I was looking forward to presenting the Heart Award with heart children Alma and Ellen and meeting some of the young people living with heart disease. Hopefully we can meet another time."
Mary's next public engagement is scheduled for Monday, when she is due to attend a School Force visit with her Foundation.
On Friday, the palace announced more travel plans for King Frederik and Queen Mary.
The couple will undertake their first tour of the Faroe Islands from 11 to 13 June, visiting Tórshavn, Vágur, Fámjin, Tvøroyri and Eiði.
© GettyThe Faroe Islands is a self-governing archipelago, located between Iceland and Norway, and is part of the Kingdom of Denmark.
The tour was due to take place last year but it was postponed due to strikes in the country at the time.
© GettyFrederik and Mary will also carry out a late summer cruise on the Royal Yacht Dannebrog from 25 to 28 August.
They will visit a number of Danish Municipalities, including Frederikshavn, Thisted, Læsø and Samsø.
© GettyIt's not known if they will be joined by their four children on their tours.
Crown Prince Christian, 19, is currently undergoing military training, while Princess Isabella, who turns 18 in April, is in the final year of her secondary education.
© GettyTwins Prince Vincent and Princess Josephine, 14, are still studying at school too.
Frederik became King of Denmark in January 2024 following his mother Queen Margrethe's abdication.
