The Prince and Princess are today attending the Installation of Dame Sarah Mullally as Archbishop of Canterbury at Canterbury Cathedral in Kent.
William, 43, is taking part in his role as heir to the throne, according to recent tradition.
The monarch, who is Supreme Governor of the Church of England, delegates the duty to their successor.
Dame Sarah is the first woman to be appointed Archbishop in its 1,400 year history, and today's service is her formal installation.
She is the 106th Archbishop of Canterbury.
William and Catherine previously met her at Lambeth Palace on February 5 and have since indicated their interest in building a warm and meaningful relationship with the most senior bishop in the church and its spiritual leader.
Upon arrival Their Royal Highnesses will be received by the Lord Lieutenant, Lady Colgrain, who will then introduce them to the Dean of Canterbury, the Very Reverend Dr. David Monteith.
The couple will process through the Nave and take their seats in the Quire.
The Prince and Princess of Wales arrive for the start of the ceremony today
The Prince and Princess of Wales are pictured during the ceremony to install Dame Sarah Mullally as the 106th Archbishop of Canterbury
Dr David Monteith (front) leads the Prince and Princess of Wales as they arrive for the Enthronement Ceremony
They have no role in the service so will simply watch as members of the congregation.
The Prince and Princess will take a few moments to speak to the new Archbishop on their way out.
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