Channel Five has climbed back on board with Project Canvas, following the broadcaster's takeover by publisher Northern and Shell.
The consortium plans to create an Internet-based TV-on-demand platform delivered via set-top box. Channel Five quit the project last month, saying it could no longer afford it.
Now Five's new owner, Northern and Shell, has reversed that decision.
"Project Canvas is set to shape the future of broadcasting and open up new and exciting possibilities for viewers," said chairman Richard Desmond. "This is important to the future of Channel Five and having an open internet-connected TV platform fits closely with our plans to bring interactive services to viewers."
The other collaborators in the scheme are UK broadcasters BBC, ITV and Channel 4, telecoms operators BT, Talk Talk, and communications company Arqiva.
Although Canvas, which is due to launch next year, has been given the go-ahead by the BBC Trust, it will still need to clear an Ofcom competition probe before it launches.