The 96-year-old monarch has become the second-longest reigning monarch in the history of the world according to People Magazine.
After celebrating 70 years on the throne earlier this month at her Platinum Jubilee, the Queen can now say she has served the UK and the Commonwealth for a total of 70 years and 127 days, surpassing King Bhumibol Adulyadej of Thailand, who was crowned in 1946 and reigned for 70 years and 126 days, before his death in 2016.
The milestone comes six weeks after she also surpassed Johann II of Liechtenstein, who died in 2016 after ruling for 70 years and 91 days.
Her Majesty's coronation was on June 2, 1953.
The longest-reigning monarch in the world was King Louis XIV of France who ruled for a total of 72 years and 110 days. He assumed the throne at age 4 in 1643 and ruled during the golden age of arts and culture in France.
Lacey noted the reason for the lack of public appearances is not only because of recent health and mobility issues but because she has "high expectations" for herself and said, "She would not want to stumble — not for her own sake but for the distress it would cause other people."
Despite her noticeable absence, she released a statement saying, "I have been humbled and deeply touched that so many people have taken to the streets to celebrate my Platinum Jubilee."
Adding, "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 humbled and deeply touched that so many people have taken to the streets to celebrate my Platinum Jubilee.”
As the #PlatinumJubilee weekend draws to a close, Her Majesty has sent a thank you message to all those who have marked her 70 years as Queen. pic.twitter.com/eoZTcrTr6C
While she's still mentally alert and continuing to carry out virtual engagements, it's now understood the Palace will no longer announce whether she will attend an event in person until the day. It will instead be assumed that Prince Charles, 73, will take her place as he has been doing for quite some time.
The Queen's inner circle and close family members have rallied around her, with her daughter Anne and daughters-in-law Camilla and Sophie keeping a close eye on her. Disgraced Prince Andrew remains her favourite and a regular visitor, while the Queen increasingly turns to Charles to represent her.