Queen Elizabeth reportedly made a concerted effort to save her energy during her Platinum Jubilee celebrations.
The 96-year-old monarch has struggled with mobility issues over recent months, and royal expert Jonathan Sacerdoti has claimed that the Queen was determined to save her energy "as best she could".
Speaking about her approach to the Platinum Jubilee celebrations, he told Us Weekly: "She was working very hard to maintain her strength.
"I think it’s totally understandable that she was saving her energy as best she could for all the events that she wanted to be at if she possibly could."
The Queen was forced her to miss a number of events during the Platinum Jubilee celebrations due to her mobility problems.
However, she was able to appear on the balcony of Buckingham Palace, when she waved to the crowds on The Mall in London.
The monarch subsequently released a statement, saying she was "humbled and deeply touched" by the celebrations.
The Queen - who is the longest-serving female head of state - said: "When it comes to how to mark 70 years as your Queen, there is no guidebook to follow. It really is a first. But I have been humbled and deeply touched that so many people have taken to the streets to celebrate my Platinum Jubilee.
"While I may not have attended every event in person, my heart has been with you all; and I remain committed to serving you to the best of my ability, supported by my family.
"I have been inspired by the kindness, joy and kinship that has been so evident in recent days, and I hope this renewed sense of togetherness will be felt for many years to come.
"I thank you all most sincerely for your good wishes and for the part you have all played in these happy celebrations."