Francis made the surprise announcement in his weekly Angelus message, which he has been delivering from inside the Vatican over the internet and television instead of before crowds in St. Peter's Square.
His decision to make an exception and give a special "Urbi et Orbi" blessing underscored the gravity of the situation worldwide but particularly in Italy, which has overtaken China as the country hardest hit by the virus outbreak.
The pope said that on Friday evening he would deliver the extraordinary blessing from an empty St. Peter's Square. The square, which is part of the Vatican, has been closed as part of a lockdown in Italy to try to contain the spread of the virus.
Catholics who receive the blessing, either in person or via the media, can, under certain conditions, receive a special indulgence. An indulgence is remission of punishment for sins.
On Saturday Italy recorded a jump in deaths from coronavirus of almost 800, taking the death toll in the country to nearly 5,000.
Francis also called on all Christians around the world to stop at noon Italian time on Wednesday to pray the "Our Father" together.
"We want to respond to the pandemic of the virus with the universality of prayer, of compassion, of tenderness," he said from the papal library. "Let's remain united."In its latest desperate effort to halt the epidemic, the Italian government ordered that all businesses must close until April 3, with the exception of those essential to maintaining the country's supply chain.