Besiktas look set to complete the signing of Guti, who has officially left Real Madrid after 15 years and 542 matches.
Guti held a press conference on Sunday lunchtime to announce his departure, flanked by the club's general manager Jorge Valdano. Marseille had also been linked with the 33-year-old Guti, full name Jose Maria Gutierrez, but appears to have chosen to move to Turkey reportedly on a two-year contract.
Guti made his debut for Real in December 1995, having joined the club as a nine-year-old. He was most instrumental in the side which won La Liga in 2001, as he scored 14 goals for the capital club. He scored 77 goals and won 15 trophies including five league titles and three Champions League medals.
Guti said: "Thank you to everyone. I go knowing that Real Madrid will always be my home. I leave knowing that Real Madrid wants me and that is very important.''
While Istanbul is Guti's expected destination, he says he has not yet finalised his future plans.
"I have an offer from Besiktas, but I haven't decided yet,'' he said. "What is for sure it that wherever I go, I will give everything. I don't know where I will end up playing, but I would like to have the possibility of carrying on at Real Madrid when my career as a footballer has ended."