So, what should he play?
Family and friends of the Prince of Cambridge celebrated the heir to the throne becoming a member of the Anglican Church with a selection of traditional hymns and music, including J. S. Bach's Fantasia in G.
The hymns to be performed are Breathe on Me, Breath of God and Be Thou My Vision, with anthems by Richard Popplewell (Blessed Jesu! Here we Stand) and John Rutter (The Lord Bless You and Keep You), performed by the Choir of Her Majesty's Chapel Royal. Blessed Jesu! Here we Stand is particularly significant, as it was written for Prince William's baptism on 4 August 1982.
Before the service, the organist played Bach's Fantasia in G, and the congregation will leave the service to Widor's Toccata from Symphony No 5.
The christening started at 3pm in the Chapel Royal at St James' Palace, as opposed to the Music Room at Buckingham Palace - where royal christenings usually take place. Known as the 'cradle of English church music', the Chapel Royal has a long musical history, with notable organists including Thomas Tallis, William Byrd, Orlando Gibbons and Henry Purcell.