Speaking to ITV News ahead of tonight's switch on in Oxford Street, Jessie J said Christmas helped put London in a good mood - which was what the capital sometimes needed.
More top news
London has welcomed in the Chinese New Year in style with the biggest party outside of Asia.
Detectives have launched a murder investigation after a man was fatally stabbed in Kensington.
The public is being urged to vote for a tree which symbolises the Scouting movement to secure a UK win in a Europe-wide competition.