BritBox will become part of ITVX when the new streaming service from ITV launches this November.
BritBox UK is currently home to over 600 pieces of Classic Doctor Who content, including a mix of episodes, spin-offs, documentaries, telesnaps and many rarely-seen treasures.
There's a total of 129 complete stories on the platform - that's 558 individual episodes - which span the first eight Doctors from William Hartnell to Paul McGann.
ITV has confirmed to TV Zone that all classic Doctor Who episodes currently available on BritBox will remain available to subscribers once BritBox is integrated into ITVX this November.
Earlier this year it was revealed that ITV had bought out the BBC's share in BritBox to allow them to better integrate it with their plans for ITVX.
Whilst BritBox will remain a separate brand within ITVX, it will require a paid subscription to 'XPremium' (the new version of ITV Hub+) to access the thousands of hours of BritBox content.
XPremium will also allow viewers to watch ITV content ad-free across ITVX.
An ITV spokesperson previous said: "To give ITV greater control over BritBox U.K. and enable its integration into ITVX, the BBC has ceased to be a shareholder in BritBox UK...
"They will continue to be a strong partner for BritBox U.K. and BritBox International, and we have agreed a new long-term content supply deal with the BBC."
ITVX will become the UK’s first integrated advertising and subscription funded (AVOD/SVOD) platform. It will allow viewers tp choose whether to watch content for free in an advertising funded tier or trade up to a subscription service which provides all that content ad-free.
In a step change to its traditional approach ITV will now adopt a digital first windowing strategy - premiering much of its new content first on ITVX and subsequently months later on ITV linear channels.
As well as being able to live stream ITV linear channels, ITVX will have an ever-changing host of exclusive themed channels, data driven to align with viewer preferences and popularity.
These constantly evolving pop-up channels will give a scheduled experience through a streaming service, with viewers able to choose where in the schedule they join.
ITVX is to launch in November 2022, the pricing to be confirmed in due course.