Britain’s King Charles opened up about his cancer diagnosis on Wednesday, saying it can be a “daunting” and “at times frightening” experience for those living with the illness.

King Charles III has shared rare personal reflections on his cancer battle in a message thanking “all those who support cancer patients and their loved ones.” The 76-year-old monarch wrote a letter posted on the royal family’s website Wednesday ahead of a reception hosted by the king and Queen Camilla at Buckingham Palace for “representatives from community-based cancer organizations and initiatives” in recognition of “their tireless work.

King Charles III has expressed his support to those living with cancer as he described how a diagnosis can be a “daunting and at times frightening” experience.