Archbishop Rino Fisichella, president of the Pontifical Council for Promoting New Evangelization, made the announcement at a Vatican news conference Nov. 18.
The bones, which were discovered during excavations of the necropolis under St. Peter's Basilica in the 1940s, have been displayed in the pope's private chapel but never in public.
Archbishop Fisichella said an urn containing the bones would be carried into the square in a procession, but said he did not know the details of the veneration ceremony, including the role of Pope Francis.
No pope has ever declared the bones to be authentic. However, after scientific tests were conducted on the bones in the 1950s and '60s, Pope Paul VI said in 1968 that the "relics" of St. Peter had been "identified in a way which we can hold to be convincing."