The Pope has been admitted to hospital for surgery to remove a growth on his lung.
Leo walked into Rome’s Gemelli hospital and waved as dozens of well-wishers waited at its main entrance.
He revealed on Sunday during his weekly blessing that doctors had found a small nodule, but that it had been detected early.
Asked by journalists on Monday whether the news had been “a bolt out of the blue”, Vatican Secretary of State Cardinal Parolin said: “no-one had expected it. But these are, as the Pope said, God’s surprises.” He added that he and Pope Leo had spoken on Monday afternoon, “very calmly. The Holy Father truly is a great example in this regard”. But the Cardinal said he was “concerned, because I certainly did not expect something like this to happen.” However he added that “Normally, when these things are caught in time, they can be resolved”.
Cardinal Parolin said there had been a great outpouring of affection for the Pope from around the world following the news of his health.
Posting on X, the Archbishop of Canterbury Rt Rev Dame Sarah Mullally promised to hold the 71 year old in her prayers and said she joined "Christians across the country and around the world" in praying for his swift recovery.
The Archbishop of Westminster Most Rev Richard Moth has "sent a message on behalf of all in the Catholic Church in England and Wales, assuring him of our prayers”.
Arriving at the hospital Pope Leo shook hands with Dr Andrea Cambieri, one of the medical team.
Prayers will be said this evening in the hospital’s St. John Paul II Chapel, led by Cardinal Baldassare Reina, the Pope’s Vicar General for the Diocese of Rome. He has invited every parish and religious community in the diocese to pray the Rosary together at 6pm local time.