World Youth Day organisers in Sydney say up to 1 billion people worldwide will watch Stations of the Cross performance on television.
The re-enactment of the last day in Jesus's life will take place around 13 sites in central Sydney on Friday.
World Youth Day spokesman father Mark Podesta says up to 1 billion people around the world will tune in.
"It's sure to be moving and inspiring and probably the event that people will remember for years to come after World Youth Day."
Tens of thousands of pilgrims will also amass at seven sites, from the Domain to the Opera House and Darling Harbour, to watch a series of Stations either live or on large TV screens.
Pope Benedict XVI will attend the first station - The Last Supper - at an invitation-only event at St Mary's Cathedral, from 3pm local time.
Further stations include Jesus before Pilate, Jesus takes up his cross, Jesus is stripped of his garments and nailed to the cross before Jesus dies on the cross and The body of Jesus is brought down from the cross event, concluding at Barangaroo at 6pm local time.
The Pope, 81, will continue his official duties in Sydney ahead of the performance.
He will host New South Wales Premier Morris Iemma and the state's Governor Marie Bashir at St Mary's Cathedral before meeting with other Christian leaders and those from different faiths.
A group of 12 young people, including New Zealander Clare Dooley, will then join the pontiff for lunch.
A Papal mass will be held at Randwick Racecourse on Sunday. Up to half a million people are expected to attend.