Primates from across the globe have gathered to join with the Archbishops of Canterbury and York to try and resolve fierce disagreements on the issue.
There's a fear a number of the 38 leaders could walk out of talks before the Friday deadline in protest.
A group, mostly from African nations, are angry at the acceptance gay marriage in the American Episcopal Church.
The African leaders argue this is unbiblical and against the teachings of Jesus.
Premier understands there will be little press updates during the meeting and those attending will be asked to leave their phones outside of the meeting room.
Revd Dr Andrew Goddard, Senior Research Fellow of the Kirby Laing Institute for Christian Ethics, told Premier it was a "miracle" so many primates had agreed to attend: "The good news is that there are going to be primates from a large number of the Churches.
"In the past not all the primates have come because of the difficulties and what we're seeing now is actually a large number of them coming."
He added: "Because of the tension and difficulties prayer is vitally important for wisdom, for love, for listening and for openness to God, that he would be able to lead those there together rather than they have in the past finding themselves apart.
"Many people thought the situation had got so broken that this wouldn't be able to happen again but the Archbishop has spent a lot of time and energy talking to them and listening to what they want to say."
On Sunday more than 100 senior Anglicans wrote an open letter to both archbishops urging them to take a "unequivocal message" of acceptance to the other leaders.
Bishop Alan Wilson told Premier: "There really is a time now for action, not just for saying sorry and saying we got it wrong and whatever we say about you we really like you, really that's not good enough.
"We've got to take action to stop some of the dreadful things that are going on around the world aimed at LGBTI people."
Susie Leafe, Director of the Anglican evangelical campaigning network Reform, told Premier the letter was not a surprise: "Knowing some of the things that those who have signed it have said in the past, I think there's a real confusion over what it means to follow Jesus as our Lord, to accept him as our saviour."
Listen to Premier's Hannah Tooley speak to Revd Dr Andrew Goddard:
