X Factor winner Alexandra Burke was joined on stage by children from Tower Bridge Primary School in Potters Fields Park on Tuesday.
The singer was the star attraction at the Quality Street Christmas Caroleoke event to promote the chocolate brand.
A snow machine provided a festive atmosphere in Potters Fields Park while the crowd joined in a number of popular Christmas songs.
Alexandra Burke was supported by members of the London City Singers, an all-female barbershop-style group.
Pupils from Tower Bridge Primary School and employees from local offices were among those who donned purple Father Christmas hats to sing along with Alexandra Burke in front of Tower Bridge.