In a statement, the 65-year-old Monegasque royal sent his warmest thoughts and prayers to Charles, 75, who is said to be on good form following treatment earlier today for an unspecified cancer.
Sources say the King's famously healthy and active lifestyle, which includes daily walks and a military-inspired exercise regime, has left him "perfectly placed to face his cancer battle"
King Charles cannot stand warm environments, often opening windows across his royal residences that have led to "constant battles" with his wife Queen Camilla, according to her sister Annabel Elliot