Masdar has agreed to pay developer Statoil 25% of previous and future costs for the 30MW floating array set for a site 25km off Scotland's east coast. Norway-based Statoil retains a 75% stake in the project.
Statoil gave the final investment decision on the project in November 2015, after receiving the final consents from the Scottish government.
The developer said the spar-buoy foundations have been constructed in Spain and will be delivered to a shipyard in Norway for assembly before making their way to Scotland in the summer.
Statoil said the agreement also includes the option to "work together on clean energy technologies across several markets" in the future.
The two companies are also partners, with fellow Norwegian developer Statkraft, at the 402MW Dudgeon offshore wind project, under construction off England's east coast.
Masdar also owns a stake in the world's currently largest offshore wind project, the 630MW London Array.
"With Masdar onboard as a strong strategic partner we are teaming up with a company with high ambitions within renewable energy. We believe Masdar can be a strong partner also in future Hywind projects and we hope that our collaboration will result in future value creation opportunities for both parties," said Statoil executive vice president of new energy solutions Irene Rummelhoff.