It will be the first funeral of a pontiff who resigned in six centuries.
The late Benedict XVI will have a funeral similar to that of a reigning pope, including a three-coffin burial, the Vatican announced on Tuesday.
The retired pontiff died aged 95 on 31 December, with a three-day lying-in-state beginning on Monday.
Benedict, a German from a small village in Bavaria, was the first pope in six centuries to retire instead of serving as the head of the Catholic church for the entirety of his life.
This unprecedented situation had given rise to questions about how the funeral would take place, with the current Pope Francis uncommonly overseeing the burial.
A written account of Benedict's papacy will be placed in his coffin for burial, the Vatican said, while revealing its plans for the funeral on Thursday.
Tens of thousands of people have paid homage to Pope Benedict so far, filing past his body in St. Peter's Basilica in the Vatican.
Hungarian Prime Minister Viktor Orban, who has called for the protection of Europe's Christian roots like Benedict, was among some of the 70,000 people paying their respects in the tiny city-state.
When the lying in state ends Wednesday evening, a one-page account of Benedict’s nearly eight-year papacy will be put into a metal cylinder and placed inside his coffin.
It will accompany other items including Vatican coins minted during his reign, said Vatican spokesman Matteo Bruni.
Benedict had an extraordinary papal retirement living out the rest of his days in a monastery in the Vatican Gardens.
Pope Francis will celebrate the funeral Mass in St. Peter’s Square.
Although the Vatican has stressed that Benedict wanted “simplicity" to characterise his funeral, Bruni said "great detail" will be paid to "pontifical ceremonies ... with some original elements."
The retirement of Benedict, who was previously known as Joseph Ratzinger, in 2013 and his succession by Pope Francis created a rare situation where there were effectively two popes.
Since Benedict was no longer a reigning pontiff when he died, official delegations have been limited to those from Italy and his native Germany.
Among those expected to attend in a private capacity were the presidents of Poland and Hungary and the monarchs of Spain and Belgium.