Featuring choirs from across London accompanied by a young brass ensemble and Harvey Brough from Harvey and the Wallbangers.
A vintage open top London bus will provide the stage for the carols and modern Christmas favourites from 6pm to 7pm.
There will also be a Christmas market providing mulled wine, mice pies, stocking fillers, decorations and crafts.
These activities will continue until 8pm with the brass ensemble backdrop.
This year's repertoire covers everything from O, Come all ye Faithful to Mariah.
Sheet music for all songs will be distributed ahead of time to participating choirs to learn the songs before the event.
The words will be handed out to the public at the event too.
The event is free but bring some change for the collection buckets - any money raised will be donated to the Waterloo Foodbank.