BBC Three was the first channel to be 'simulcast', back in February this year.
BBC Four, CBBC and CBeebies soon followed but the announcement means that BBC One and BBC Two will be available online for the first time.
Jana Bennett, director of BBC Vision, said: "The launch of BBC One and BBC Two online completes our commitment to make our portfolio of channels available to watch on the internet."
The BBC did indeed promise back in June this year that the channels would be online before the end of 2008.
The channels will only be available to surfers in the UK.
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