The BBC has brought forward its launch of five new subscription-free HD channels in time for Christmas.
The new channels, which will launch on Tuesday, are BBC Three HD, BBC Four HD, BBC News HD, CBeebies HD and CBBC HD.
They will all be available on Freeview HD, Sky HD, Freesat HD, YouView, and Virgin Media.
Tony Hall, the BBC's director general, said: "This year, people will be able to watch even more of our programmes in brilliant quality."
"I am delighted that we're able to launch our new HD channels in time for Christmas, when families gather to enjoy some of the best TV from the BBC."
The BBC launched its first HD channel, appropriately named BBC HD, in 2006, showing a range of programmes from across the corporation's channels.
The service was followed by BBC One HD in 2010 and, earlier this year, it was replaced by BBC Two HD.
More than 50% of homes in the UK are HD enabled but it is estimated this will rise to more than 80% by 2018 and more than 90% by 2019.
BBC Three HD and CBBC HD will use existing BBC HD capacity on Freeview HD and YouView, which covers all UK homes.
The new channels for BBC News, BBC Four and CBeebies will use new HD capacity, which will cover 70% of UK homes by June next year.
Writing in her blog, the director of BBC distribution, Alix Pryde, said: "In July 2013, we confirmed our intention to launch our five new HD channels by early 2014. But we couldn't resist the possibility of being able to deliver these early, in time to give them to you for Christmas.
"It's said that launching a channel takes at least six months. We will have managed to launch five channels in five months. So I want to take this opportunity to say a huge thank you to the brilliant team of dedicated professionals, across the BBC, our suppliers and our platform partners, who have been pulling out all the stops to achieve this for our audiences."