It has been one of the most intensely scrutinised party leadership races in memory with left winger Jeremy Corbyn rising from rank outsider to overwhelming favourite.
Here's how the announcement will play out on Saturday and exactly when you can find out if Labour really will Corbyn its next leader:
- 10.00am: Corbyn, Andy Burnham, Yvette Cooper and Liz Kendall will arrive at the Queen Elizabeth II Conference Centre's "candidates' holding room" in Westminster.
- 10.30am: The candidates will be informed of the final result but be sworn to secrecy.
- 11.00am: Special conference opened by chairman of the National Executive Committee Jim Kennedy, results of the deputy leadership contest to be announced first. Tom Watson - another left wing candidate - is the favourite ahead of Stella Creasy, Caroline Flint, Angela Eagle and Ben Bradshaw.
- 11.30am: Results of the leadership contest announced. New leader to deliver speech.
- 3.00pm: The new leader will meet with senior management of the party.
Where can I watch it unfold?
- BBC Two will cover the result as it happens from 11am - 12pm.
- The new leader will conduct their first interview in the role with Andrew Marr on Sunday morning at 9.00am on BBC One.
How does the voting process work?
Labour are using the one member one vote system for the first time, meaning all members and registered supporters all have one vote each. This is one of the factors credited for Corbyn's likely victory.
The result is tallied using the alternative voting system. If no candidate wins over 50 per cent of the first preference votes, the person in last place drops out and their second preferences are added to the count. This process is repeated until the candidate with the most votes emerges.