The Moderator of the Church of Scotland, Right Reverend Albert Bogle, will lead prayers in the Glasgow city centre building at the weekend with the church's new congregation but it is unclear if a service will be held there on Christmas Day.
The acrimonious split has been further marred by legal disputes and the former congregation – now know as the Tron Church – left the building for prayer halls and held its first service there on December 9.
Both sides agreed to the handover of keys so services could be held.
Rev Stuart Smith, interim Moderator of the General Assembly of the Church of Scotland St George's Tron congregation, said: "A special service in planned for this Sunday afternoon at 3pm, led by the Moderator of the General Assembly of the Church of Scotland, the Right Reverend Albert Bogle, and all are welcome.
"Other activities are also being planned. We cannot confirm a Christmas Day service as yet."
A spokesman for the Tron Church – which quit after the appointment of openly gay minister Scott Rennie – said it is "focusing on its own programme of services" which includes services at its Bath Street halls on Sunday, Christmas Eve and Christmas Day.
The news came as a Kirk minister accused the break-away church's leaders of "robbery" by setting up funds for its new congregation ahead of quitting.
Former leader of the Iona Community Ron Ferguson also said the Tron used heavy handed tactics in forming the group that split.
As they vacated the landmark city centre St George's Tron Church building, writs were served on the Rev Dr William Philip to prevent him removing items including chairs and Bibles from the church. It is claimed the Kirk is still owed a £1 million debt and now a further wrangle over the manse looms.
Author and newspaper columnist Mr Ferguson wrote in the online magazine Scottish Review: "So how did they get away with it? The Great Tron Robbery, I mean. Or, more expansively, the Great Tron Public Relations Robbery."
A spokesman for The Tron denied it owes £1m, bullying or wrongly setting up funds.
He said: "Ron Ferguson's comments are as mischievous as they are without foundation. A very tiny handful wished to remain in the Church of Scotland, but allegations about bullying are quite untrue."