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
Police are hunting a man who is suspected of grabbing an 11-year-old girl who only got away by biting her attacker's hand.
A woman and man have been charged with murder after a baby was found unresponsive on a bus.
Rebecca Casserly was on her way to buy a coffee in north London when her phone was suddenly snatch from her hand by a man riding a bike.