The queen's experience with keeping a significant secret has been shared. Camilla found it difficult to keep the king's cancer diagnosis private. She discussed the challenges during a visit to a cancer support center. The visit took place before the official public announcement of the diagnosis.

The queen's comments were made during a visit to a Maggie's center, a charity that supports cancer patients. Her remarks were featured in a short film released to mark the charity's 30th anniversary.

Further details about the queen's experience and the charity's work are available from the source, including a visit to a newly opened center in a London hospital.