Mulroney tells The Canadian Press that Roy died of cancer at the Montreal General hospital on Wednesday.
Mulroney called Roy an extremely close friend.
Roy served as Mulroney's principal secretary from 1984 to 1988 and was described by the former prime minister as a great athlete and a highly accomplished lawyer.
Mulroney says his friend of 50 years played a key role in the Meech Lake accord, the Canada-U.S. Free Trade agreement, the treaty on acid rain and the creation of the summit of la Francophonie.
A church service will take place March 27 at Saint-Leon-de Westmount Church in Montreal.
Mulroney said he first met Roy at law school at Universite Laval.
Roy was best man at Mulroney's wedding.
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