Zara Phillips is set to marry fiance Mike Tindall in Scotland.
The 29-year-old equestrian - who is the daughter of Princess Anne and her first husband Captain Mark Phillips - reportedly has her heart set on tying-the-knot on Edinburgh's Royal Mile on July 30.
The queen's granddaughter and the rugby player want to marry at Canongate Kirk with a reception likely to follow at the monarch's nearby Palace of Holyroodhouse.
The news emerged after the church's minister, the Reverend Neil Gardner, asked another young couple to move their wedding to avoid a clash.
Edinburgh couple Cherith Harrison and Gregg Walter, both 27, have now switched their ceremony to Greyfriars Kirk to make way for Zara's request.
Father of the bride Robert Harrison, managing director of a car dealership, told Britain's Daily Express newspaper that they had been "quite happy" to step aside for the royal wedding and it had "not caused any problems".
Rev Neil Gardner said he could not comment on the nuptials but added: "I'm sure there will be an announcement."
The Canongate Kirk is the parish church for the Palace of Holyroodhouse where Queen Elizabeth, 84, attends services when she is staying in the city.
The nuptials will come three months after Zara's cousin Prince William's wedding to Kate Middleton at Westminster Abbey on April 29.