TRIG bought the stake from Global Infrastructure Partners for an undisclosed sum.
On completion of the transaction, expected at the end of the first half of this year, Hornsea One will represent about 8% of TRIG's portfolio by value, the company said.
Hornsea One is the largest operational offshore wind farm in the world and has been running since 2020. With capacity of around 1.2 gigawatts (GW), it generates enough electricity to power 1 million homes.