Christopher Warren-Green first conducted for the royal family in 1980, when Prince Charles asked him to perform in the ballroom at Buckingham Palace.
"The prince and I go, in his words, back a long way, and that is a relationship I hold very dear," Warren-Green told WSOC.
He's conducted for the family several times, including the wedding of the Duke and Duchess of Cambridge in 2011.
"Nothing actually went wrong in that wedding (crossing fingers). You really can't afford to have anything go wrong in those. You really can't," he explained.
This time, Warren-Green said he is planning a musical experience that will be kept a secret until the big day.
"The theme - just like anybody's wedding - has to reflect something, and what that something is I'm not going to say. It's top secret - can't say."
Warren-Green said the hardest part of conducting a royal wedding is timing out the processionals.