They're the fifth and sixth companies to sign up, joining the Beeb, ITV, Channel Five and BT, which means all of the UK's terrestrial channels and their internet catch-up services are on board.
This gives the project, which still needs approval from the BBC Trust, a real momentum boost, and paves the way for the arrival of Project Canvas set-top boxes in the new year.
These are expected to cost between £100 and £200, and will be hi-def, PVR-equipped versions of web players like iPlayer, ITV Player, Demand 5 and, now, 4oD.
But it won't all be plain sailing for the project – Sky has criticised it for being an anti-competitive merger, and Sony has expressed concerns that its UK-centric tech makes manufacture a headache. We'll bring you more news as we get it.