Swansea City boss Graham Potter has been unveiled as the new Brighton manager.
Swansea had offered Potter a new contract in an attempt to ward off interest from the Seagulls, who sacked Chris Hughton following the end of the Premier League season.
However, after the Championship side initially rejected Brighton's approach, former Ostersund boss Potter completed the formalities of a four-year deal ahead of being unveiled on Monday afternoon.
Swansea City chairman Trevor Birch has said the club is disappointed.
Potter, who turned 44 on Monday, had two years left on his current deal at the Liberty Stadium.
Appointed last summer, Potter guided the Swans to a 10th-place finish in the Championship last season.
Potter was credited with playing an attractive brand of football, even though financial constraints at the Welsh club saw him lose 16 first-team squad members.
Brighton will be hoping Potter, who won three promotions with Ostersund and steered them into the Europa League, can help move the south-coast club forwards.
Potter was officially unveiled at a press conference at Brighton's training ground on Monday, which also marked his 44th birthday.
He began by thanking his former club before looking forward to the challenges ahead.
"It is a fantastic opportunity for me. I am very excited, I am aware of the responsibility that I have," he said. "I am looking forward to getting further and further into the football club and working eventually with the players.
"In the meantime, I will get on with the planning and preparations you need for a Premier League season."
Potter revealed there had been a couple of days of "intense conversation" with Brighton as he considered their approach.
"The project we had at Swansea was very challenging, but still we were in the middle of that," he said.
"Once I had spoken with the guys here, understood their vision and what they wanted to achieve... there are a lot of good people at this football club and I am excited to be here."