The companies have signed a 50:50 partnership to progress with the project. The project team will be lead by Statkraft but combine RWE and Statkraft personnel.
Financial details of the deal have not been released.
Triton Knoll is still in a consultation stage of the process, with a view to submit plans for its onshore electrical system to the UK's planning inspectorate later this year. RWE received planning consent from the government in July 2013.
Offshore construction is due to begin in 2018 and the project is estimated to be online by 2020.
The project was being developed solely by RWE, but part of its offshore strategy is to find equity partners for its projects.
Statkraft is a co-developer of the 317MW Sheringham Shoal and the 402MW Dudgeon projects in the North Sea.