He joins Palace after spending a season on loan at Real Betis for whom he played 30 times in all competitions.

"The club has high-level players who are young and I have come here to follow their same trajectory, to grow as they have grown," Riad said in a club statement.

Riad was born in Palma, Mallorca, to Moroccan parents and came through the island club's youth system before moving to Barcelona and graduating from the La Masia academy. He made only one appearance for Barcelona's first team.

He has earned three senior caps for Morocco, debuting against Sierra Leone in January and scoring his first international goal against Congo earlier this week.

Riad is Palace's first arrival of the transfer window which opened on Friday.

On the defender's arrival, club chairman Steve Parish said: “As a full international at just 20-years-old, Chadi is an exciting young player who we are delighted to be able to welcome to the club.

"His arrival adds quality to a squad already packed with talent and potential, and I look forward to seeing him contribute to the team this season and beyond.”