Prince William said his wife Catherine is "doing well" following her cancer diagnosis.
The Prince of Wales made the remarks on a visit to St Mary's Community Hospital on the Isles of Scilly.
He was told about a new health and social care facility being built on Duchy land near the hospital.
William said George, Charlotte and Louis were "very jealous" of his trip, and said he may bring them to Cornwall later in the year.
He was given a letter by matron Lynda McHale, written by her granddaughter, that wished Catherine and the King well in their respective cancer recoveries.