Ahmed Hegazi has joined Al-Ittihad on loan from West Brom until the end of the season, when he will sign a permanent deal with the Saudi club.
The 29-year-old Egypt defender scored four goals in 104 appearances for the Baggies after joining from Egyptian side El Ahly in 2017.
He made 14 starts last season as West Brom won promotion to the Premier League from the Championship.
Al-Ittihad are eight-time Saudi Professional League champions.
They are currently 11th after picking up just one point in their opening two games of the season.