West Bromwich Albion have signed defender Semi Ajayi from Rotherham United on a four-year contract, for an undisclosed fee.
The 25-year-old made 108 appearances for the Millers following a move from Cardiff in July 2017, helping them win promotion to the Championship.
Ajayi, who began at Charlton and also played for Arsenal and AFC Wimbledon, has made 160 career appearances.
"It's a great opportunity for me," the Nigeria international said.
"I want to play at the highest level and I have joined a club with the ambition to get there."
He joins Kenneth Zohore and Filip Krovinovic as new arrivals at the Hawthorns this summer.
Find all the latest football transfers on our dedicated page.