West Ham have completed the signing of Nayef Aguerd from Rennes for a reported fee of £30million including add-ons (€34.9m).
The Morocco international joins on a five-year deal as Hammers manager David Moyes strengthens his backline ahead of next season.
The defender featured in 66 Ligue 1 games for Rennes after joining in 2020, while also helping his country to qualify for the World Cup in Qatar after overcoming DR Congo 5-2 on aggregate over two play-off matches.
West Ham struggled with injuries last season, especially at centre-back, but Aguerd provides much-needed depth ahead of another challenge for the European qualification spots next season.
"I am delighted to welcome Nayef to West Ham United. We have tracked his progress for some time and I'm very pleased that we have been able to complete the signing," Moyes told the club's official website.
"He's a great addition that will add to our defensive options."
Aguerd pinpointed the interest of Moyes as a crucial factor for him joining the 2021-22 Europa League semi-finalists.
"I was really excited when I heard about West Ham United's interest," Aguerd said after penning his contract with the Hammers.
"I talked with the manager and he showed me that he was very interested, so it was easy to choose to come to West Ham."