Sean Brady, Catholic Primate of All
Ireland, will take the unprecedented step of accepting an invitation to the couple's marriage in
London's Westminster Abbey on April 29.
It is the first time an Irish churchman in his position will have attended a royal wedding.
It is understood the invitation is attributed to Cardinal Brady's outspoken contribution to the peace process.
He has been the first Catholic primate to attend a Church of Ireland general synod, to attend the installation of a Presbyterian moderator, and to meet members of the
Orange Order as well as loyalist paramilitaries, and he was the first to meet the Rev Ian Paisley.
Cardinal Brady has also welcomed
Queen Elizabeth II's forthcoming visit to the Republic, describing it as an important religious and civic event.