The August 25 Festival of Families concert will celebrate families and their faith from all around the world.
Over 70,000 people will take part, organisers have said.
The singer said: "Singing before Pope Francis is a privilege for our soul; it is an honour for what the Supreme Pontiff represents in the world.
"For the indescribable human fragility, typical of the average man such as myself, it brings me great pleasure and immense satisfaction to even have the privilege to be close to a person of such exceptional importance and grace.
"It is a joy to be able to offer my most modest contribution on the occasion of this grand meeting and moment of reflection about the family.
"The family remains the strongest building block of society, a cluster of affection, and a privileged space in which one can teach and learn - in every action - how to choose a life that leads toward the greater good."
Father Timothy Bartlett, secretary general of the World Meeting of Families 2018 event, said he was delighted.
"He will bring so much to our gathering not just because of his wonderful talent but because of his love for his faith.
"We are honoured that he has taken time out of an intensely busy schedule to come to Ireland to be part of our global celebration of family life."
Bocelli has met Pope Francis and has performed for him on more than one occasion including at the last World Meeting of Families which took place in Philadelphia in 2015.
He is a devout Catholic and he has spoken openly many times about the importance of faith and how it takes first place in his life.
He has regularly donated his time and talent to causes and events that he is passionate about.
Bocelli will join other well-known acts already announced for the event including Nathan Carter, Daniel O'Donnell and Moya Brennan.
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