Barack Obama, Queen Elizabeth, and Princess Charlene Lead Tributes to Desmond Tutu: 'a Moral Compass'

Rodger Bosch/AFP via Getty

Barack Obama, Queen Elizabeth, Princess Charlene, and many others are paying tribute to Desmond Tutu.

On Sunday, the Desmond and Leah Tutu Legacy Foundation confirmed the South African civil rights icon's death. He was 90.

In a statement, Obama, 60, wrote: "Archbishop Desmond Tutu was a mentor, a friend, and a moral compass for me and so many others. A universal spirit, Archbishop Tutu was grounded in the struggle for liberation and justice in his own country, but also concerned with injustice everywhere."

RELATED: Desmond Tutu, Anti-Apartheid Human Rights Activist and Nobel Peace Prize Winner, Dies at 90

"He never lost his impish sense of humor and willingness to find humanity in his adversaries, and Michelle and I will miss him dearly," the former president added, alongside a photograph of himself and Tutu hugging.

Queen Elizabeth, 95, said in her own statement, which was obtained by PEOPLE, "I am joined by the whole Royal Family in being deeply saddened by the news of the death of Archbishop Desmond Tutu, a man who tirelessly championed human rights in South Africa and across the world."

"I remember with fondness my meetings with him and his great warmth and humour," she continued. "Archbishop Tutu's loss will be felt by the people of South Africa, and by so many people in Great Britain, Northern Ireland and across the Commonwealth, where he was held in such high affection and esteem."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Monaco's Princess Charlene, 43, also paid a touching tribute to her longtime friend and ally on Sunday.

The South Africa-raised royal posted two photographs of herself and Tutu on Instagram, writing, "My dear friend, you will be missed."

"I know that you are at our fathers [sic] side. I will always have fond memories of us. And your laughter will remain in my heart forever," she added. "Rest In Peace. ❤️."

The photos are from a July, 2018, visit Charlene made to the Nelson Mandela Foundation headquarters in Johannesburg. Charlene's friendship with the late activist stretches several decades. In 2011, she visited the Archbishop's charity foundation during her honeymoon in South Africa and has long been a co-patron of the Archbishop's Giving Trust, a Cape Town-based foundation dedicated to fighting Aids in Africa.

Prince Harry and Meghan Markle issued a joint statement referencing their 2019 trip to South Africa with baby Archie.

"Archbishop Tutu will be remembered for his optimism, his moral clarity, and his joyful spirit. He was an icon for racial justice and beloved across the world. It was only two years ago that he held our son, Archie, while we were in South Africa – 'Arch and The Arch' he had joked, his infectious laughter ringing through the room, relaxing anyone in his presence. He remained a friend and will be sorely missed by all," they shared.

Valery Hache/AFP via Getty

President Joe Biden and First Lady Dr. Jill Biden also issued a joint statement in Tutu's memory.

"On this morning after Christmas, we are heartbroken to learn of the passing of a true servant of God and of the people, Archbishop Desmond Tutu of South Africa," their statement began.

"On behalf of the Biden family, we send our deepest condolences to his wife Leah and their children, grandchildren and great-grandchildren. And on behalf of the people of the United States, we send our deepest condolences to the people of South Africa who are mourning the loss of one of their most important founding fathers," the statement concluded.

RELATED: President Biden and First Lady Spread Holiday Cheer, Talk About New Puppy at Children's Hospital

Cyril Ramaphosa, the President of the Republic of South Africa, mourned Tutu's death on Twitter on Sunday.

"The passing of Archbishop Emeritus Desmond Tutu is another chapter of bereavement in our nation's farewell to a generation of outstanding South Africans who have bequeathed us a liberated South Africa," he wrote.

"Desmond Tutu was a patriot without equal; a leader of principle and pragmatism who gave meaning to the biblical insight that faith without works is dead. We pray that Archbishop Tutu's soul will rest in peace but that his spirit will stand sentry over the future of our nation," Ramaphosa, 69, continued.

Elsewhere, the Dalai Lama wrote a letter to the Archbishop's daughter, Mpho Tutu van Furth, after learning of his death.

"Please accept my heartfelt condolences and convey the same to your mother and other members of your family. I pray for him," the Dalai Lama wrote. "As you know, over the years, your father and I enjoyed an enduring friendship. I remember the many occasions we spent time together, including the week here at Dharamsala in 2015 when we were able to share our thoughts on how to increase peace and joy in the world. The friendship and the spiritual bond between us was something we cherished."

RELATED: Surprise! Meghan Markle and Prince Harry Take Archie on His First Official Outing in South Africa

"Archbishop Desmond Tutu was entirely dedicated to serving his brothers and sisters for the greater common good," the Dalai Lama, 86, continued. "He was a true humanitarian and a committed advocate of human rights. His work for the Truth and Reconciliation Commission was an inspiration for others around the world."

He added: "With his passing away, we have lost a great man, who lived a truly meaningful life. He was devoted to the service of others, especially those who are least fortunate. I am convinced the best tribute we can pay him and keep his spirit alive is to do as he did and constantly look to see how we too can be of help to others."

On Twitter, Malala Yousafzai shared a set of pictures of herself and Tutu as she honored the late human rights activist with one of his own quotes.

"'Do your little bit of good where you are; its those little bits of good put together that overwhelm the world,'" she wrote. "A kind soul left us today. Let's honour him and do our bit of good. Rest in peace Desmond Tutu."

Boris Johnson noted in a tweet that he was "deeply saddened" by Tutu's death.

RELATED: Meghan Markle and Prince Harry Share Monday Motivation Quote: 'Wishing You a Wonderful Week Ahead'

"He was a critical figure in the fight against apartheid and in the struggle to create a new South Africa - and will be remembered for his spiritual leadership and irrepressible good humour," he wrote.

Born in the former province of Transvaal in 1931, Tutu served as Bishop of Johannesburg from 1985 to 1986 before becoming the Archbishop of Cape Town from 1986 to 1994.

Tutu was awarded a Nobel Peace Prize in 1984 after being nominated thrice prior in '81, '82, and '83 for his non-violent tactics in dismantling apartheid. South Africa eventually held its first democratic, non-racial elections in 1994.

Tutu is survived by wife Nomalizo Leah Tutu and four children, Trevor Thamsanqa Tutu, Naomi Nontombi Tutu, Theresa Thandeka Tutu and Tutu van Furth, alongside their families.