30-year-old Rafael has joined the Turkish champions after five years in Ligue 1 with OL.
He has penned a two-year contract with the option of a third year, and will wear the number four shirt.
✍ HOŞ GELDİN @orafa2
— İstanbul Başakşehir 🏆 #TürkiyeninYeniŞampiyonu (@ibfk2014) September 8, 2020
Rafael made 139 appearances in total for Lyon, scoring two goals and registering 11 assists.
He first made a name for himself with Manchester United, who he played for along with twin brother Fabio (now of Nantes)