The 21-year-old Iranian, who also plays for the national team (2 caps), signed a contract with the Belgian club until 2024. The contract also includes a two-year club option.
Hosseinzadeh enjoyed his youth training in his own country with Moghavemat Tehran. In 2018, he joined Saipa, where he made his professional debut in the Iranian football league.
Last season, the attacking midfielder played for FC Esteghlal, winning the championship without losing a league match.
Hosseinzadeh played 30 games for Esteghlal last season in the Iran league and scored eight goals.