If it is built to the full capacity, the investment would total about £6bn. Hornsea Project Two will deliver up to 1,800MW of low carbon electricity, serving about 1.8 million UK homes.
Up to 1,960 construction jobs are expected to be created in building the wind farm, followed by 580 operational and maintenance jobs.
The decision was made on the merits of the scheme based on a report and recommendation from the Planning Inspectorate.
Clark said: “The UK’s offshore wind industry has grown at an extraordinary rate over the last few years, and is a fundamental part of our plans to build a clean, affordable, secure energy system.
“Britain is a global leader in offshore wind, and we’re determined to be one of the leading destinations for investment in renewable energy, which means jobs and economic growth right across the country.”
The wind farm will be located approximately 89km off the Yorkshire coast and will comprise up to 300 wind turbines, connected to the grid at North Killingholme in North Lincolnshire.