The Prince of Wales is due to speak at the Prayer Book Society's annual conference in Oxford.
Prince Charles is to deliver the event's inaugural address at an evening reception at Lady Margaret Hall, a spokesman for Clarence House said.
Charles is a patron of the society, which promotes the use of the 1662 Book of Common Prayer.
The Prayer Book is the traditional service book of the Church of England, containing its historic beliefs.
This year's conference, running from Friday to Sunday, also marks the 450th anniversary of the death of Thomas Cranmer, who became the first Protestant Archbishop of Canterbury under Henry VIII.
Cranmer was burned at the stake in Oxford in 1556 by the Catholic Queen Mary I.
Other speakers at this year's conference include the Rt Rev Anthony Burton, Bishop of Saskatchewan in Canada, and the novelist PD James.
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