Swansea - Dutch defender Mike van der Hoorn has joined compatriot Leroy Fer at Swansea City on a three-year contract, the English Premier League club confirmed on Wednesday.
The 23-year-old van der Hoorn signs a day after the Swans confirmed the arrival of midfielder Fer from QPR for an undisclosed fee.
The former Holland Under-21 international also strengthens manager Francesco Guidolin's central defensive options following Kyle Bartley's loan move to Leeds.
Van der Hoorn will vie for selection with Federico Fernandez, Jordi Amat and club captain Ashley Williams.
"I have to improve and be better," van der Hoorn told the club's official website. "I saw Ashley Williams at the European Championships. He's a really good defender, maybe I can learn from him.
"I spoke to (Fer) last Saturday - we have the same birthday - about Swansea. (He said) 'It's a real warm club, a family club, the players will be nice'. (It was a) quick response.
"This is the best competition in the world. I'm happy to be in it and can't wait to start. Maybe (we can win) the FA or Capital One Cup. That would be a nice achievement.
"(Swansea) play really good football for a Premier League club."
Van der Hoorn arrives in Wales after three years at Ajax, where he won the Eredivisie title after joining from Utrecht.