Newly released details about the wedding's musical service reveal that the first hymn sung will be "Guide Me, O Thou Great Redeemer" -- the final hymn at Princess Diana's funeral, and was also played at a memorial service on the 10th anniversary of her untimely death.
Before the service begins, a selection of organ pieces will be played, plus seven orchestral pieces by Bach, Edward Elgar, Benjamin Britten and other, mostly British composers.
Three of those pieces -- Sir Peter Maxwell Davies' Farewell to Stromness, William Walton's Touch Her Soft Lips and Gerald Finzi's Romance for String Orchestra Op. 11 -- were played at Prince Charles' and Duchess Camilla's 2005 wedding.
"Catherine is a fan of classical music and also had a lot of input from the Prince of Wales. They spent a lot of time listening to the music together on iPods," a Palace spokesman tells Us Weekly.
"The theme of [this selection for the wedding] is Britishness, accentuating traditional forms and crafts," the spokesman explains, adding that the selections will "give a sense of grandeur [to the day]."
Two selections are also sentimental for the Prince and future Princess. Middleton chose the song "Greensleeves" because "it's such a famous piece of English music," a royal insider says.