Guti has announced he will leave his role as Real Madrid youth team coach to become the new assistant manager at Besiktas.
The 41-year-old had previously been in the running to replace Zinedine Zidane at the Bernabeu prior to the appointment Julen Lopetegui.
He was also among the interview candidates for the managerial role at St Mirren before Alan Stubbs signed a three-year contract.
The former Real Madrid midfielder, who will work alongside current Besiktas manager Senol Gunes, joined the Turkish club as a player from 2010-11 before his retirement in 2012.
"Today I want to thank Real Madrid my home, for all the years that I enjoy as a footballer and as a coach," Guti said on Instagram on Wednesday.
"I will join in a few days Besiktas my house as a second coach to continue growing professionally.
"I am grateful to Besiktas for the love and trust that you have placed in me, I will return it to you with a lot of work and enthusiasm.
"My family and I are looking forward to this adventure in Istanbul, let's go for it! Always Black Eagles."