Viewers will be able to see more BBC programmes in HD from tomorrow with the launch of five new channels.
The subscription-free services will give high-definition versions of BBC3, BBC4, BBC News, CBeebies and CBBC.
The corporation announced in the summer that it was providing further HD channels, but it has brought the launch forward from early next year.
BBC director-general Tony Hall said: “I am delighted that we’re able to launch our new HD channels in time for Christmas, when families gather together to enjoy some of the best TV from the BBC.
“This year, people will be able to watch even more of our programmes in brilliant quality.”
More than half of UK homes are estimated to be capable of receiving HD.
Not all homes in the UK will be capable of receiving some of the new services. News, BBC4 and CBeebies will use new capacity for Freeview and YouView viewers and the BBC says coverage will extend to 70% of UK homes by June.