Southampton have signed central defender Jan Bednarek from Polish club Lech Poznan.
Poland under-21 international Bednarek has agreed a five-year contract and will link up with his new teammates when he returns from international duty at the European Under-21 Championship.
Bednarek, 21, helped Lech Poznan to a third-placed finish in Poland last season and told Southampton's official website he was "so happy" to have joined the club.
"This is the moment I have worked for that makes my dreams come true," he said.
"It only gives me motivation to work hard, to show my skills and to help Southampton to get better and better.
"I think it's a good step for me, because I have heard Southampton is such a good club for young players, so I can improve here. I think it will be a good move for me."
Meanwhile, Saints defender Jack Stephens has signed a new five-year deal.
The 23-year-old won a first-team place after Virgil van Dijk suffered a season-ending injury in January.
And striker Sam Gallagher, who played on loan for Championship club Blackburn last season, has put pen to paper on a new four-year deal.