Channel 4 and BBC Worldwide will retain their independence, with each owning half of the new venture, which is to be called 4 Worldwide.
John Smith, the chief executive of BBC Worldwide, and Andy Duncan, the chief executive of Channel 4, will retain their existing roles with a new management team appointed to run 4 Worldwide.
The joint venture will comprise Channel 4's E4, More4 and Film4 digital channels and some elements of BBC Worldwide. However, what these are is not clear. They could be the BBC's UKTV channels that it currently operates with Virgin Media.
This was hinted at by Smith who on Sunday wrote in The Sunday Times that BBC Worldwide was willing to include "non-BBC branded UK television businesses".
This would appear to refer to the recently rebranded UKTV channels including Albi, Blighty, Dave and Eden as well as UK History and Gold.
It might also include 2Entertain, its DVD distribution operation. However, it is thought unlikely that it will include some of the BBC's other UK commercial interests such as its magazines group of which Radio Times and Top Gear are part.
Last month Lord Carter's interim Digital Britain report said it favoured putting a "re-cast" Channel 4 together with BBC Worldwide, ahead of merging it with Five. This was echoed by Andy Burnham, the Culture Secretary, who said that he wanted Channel 4's future to lie in a tie-up with BBC Worldwide.