The Queen will not attend the COP26 climate change summit in Glasgow following medical advice to rest.
She resumed public engagements on Tuesday by meeting ambassadors via video link from Windsor Castle.
Buckingham Palace said she "regretfully" decided not to attend a reception at the summit.
But the palace said she would deliver her address to delegates using a recorded video message instead.
The Queen was due to travel to Scotland as part of a string of COP26 engagements by senior members of the Royal Family including the Prince of Wales, the Duchess of Cornwall and the Duke and Duchess of Cambridge between 1-5 November.
The other royals will still attend the summit.