Khan offcially backed the plans for Barking Riverside, a 180-hectare brownfield site, the largest single regeneration project in London, previously home to three power stations and landfill.
The site will be owned by a joint venture between the Greater London Authority and housing association London & Quadrant.
It will provide a minimum of 35 per cent affordable homes, but plans include a provision to raise this to 50 per cent over time through additional investment and viability reviews.
One of Khan's key manifesto pledges was a target for 50 per cent of all new homes in London to be affordable.
Announcing the project, he said: “Barking Riverside has enormous potential to deliver thousands of the much-needed homes Londoners so urgently need.
“I’ve made it clear that tackling London’s housing crisis is my number-one priority. Fixing this problem will be a marathon, not a sprint, but developments like this one will play a huge part in our efforts to provide genuinely affordable homes to buy and rent.
“Our next task is to ensure this development includes the facilities and infrastructure which will make this a fantastic place to live and to visit, rather than simply a housing development.”
Leader of Barking and Dagenham Council, councillor Darren Rodwell, said the project would come as part of plans for 45,000 new homes and 10,000 new jobs in the borough over ten years.
“We are committed to ensuring that no-one is left behind. These homes should serve local residents too and therefore providing affordable housing is key,” he said.