The three finalists, Christopher Maloney, James Arthur and Jahmene Douglas sang Silent Night to the crowd as the 20ft fir tree’s lights were switched on.
Following the ceremony, Christopher tweeted: ‘Just turned on the lights at Downing St to raise awareness and help for a charity or kids who only live short lives. So humbled’.
All three finalists will be visiting their hometowns in the lead up to Saturday’s X Factor final. Who is your favourite to win this weekend?
To read more about Nicole Scherzinger saying Simon rings her all the time, go to X Factor gossip