Barack Obama has paid tribute to the Queen on her Platinum Jubilee, thanking her for her "steadfast stewardship" as a leadership figure not just to the UK, but the world.
The former US president met the Queen on a number of occasions during his time in the Oval Office, visiting her in Buckingham Palace in state visits.
Noting her solid presence at the helm of the nation, Obama said it would be an "understatement to say the world has changed a bit in the seven decades since you came to power, but your character never has".
In a full televised statement recorded as part of the celebrations, Obama said: "When you're president of the United States you meet a lot of remarkable people and you try under all circumstances to maintain your composure. But that's harder than you think when you're visiting Her Majesty.
"Before I took office, Michelle and I hadn't visited many palaces, so we weren't sure what to expect on our first trip to Buckingham, but we shouldn't have been worried.
"Her Majesty put us at ease with her grace and generosity, so much so that I walked away thinking that she actually reminded me a little bit of my grandmother. And in the years since I like to think that Her Majesty and I have formed a special relationship of our own.
"Certainly I can say that getting to know her was one of the great privileges of my years in office and I learned so much from seeing the example she made for all of us who have the privilege to serve.
"Your Majesty, it would be a privilege and an understatement to say the world has changed a bit in the seven decades since you came to power, but your character never has. Your steadfast stewardship of one of our most important democracies has made the world safer, and more prosperous through war and through peace, times of adversity and times of prosperity.
"Your life has been a gift, not just for the United Kingdom, but for the world. And it is with gratitude for your leadership and the kindness that you've shown me and my family that I say, may the light of your crown continue to reign supreme."
Emmanuel Macron referred to the Queen as the "golden thread that binds" the UK and France together
The French President issued a video statement in Twitter, in which he spoke in English to mark the occasion.
"Madame, during the past 70 years the president of the French Republic has relied on very very constants at an international level. Times have changed, Europe has evolved, our continent is again experiencing war. Through these transformations, your devotion to our alliance and to our friendship has remained, and has helped build the trust that brought freedom and prosperity to our continent.
“Since your first state visit to France, when you were welcomed to Paris by a generation who, alongside your Army, Navy and Air Force, had fought for the freedom we now enjoy, you have visited us many times. You have shared our joys and seen the deep affection and admiration that the people of France have for you.
“You have also visited the graves where so many of your young men lie and seen the respect and honour we constantly pay to those who sent from your homes to protect ours.
“You are the golden thread that binds our two countries. The proof of the unwavering friendship between our nations.”