Roma have announced the signing of Turkey international Cengiz Under from Basaksehir for €13.4 million.
Under, 20, has signed a five-year contract with the Serie A club and becomes their fifth signing of the summer.
"I'm delighted to be here and very excited about meeting the fans," the midfielder told the club's official website upon signing. "My aim is to earn myself a regular starting berth as quickly as possible."
Roma could pay a further €1.5m in bonuses to Basaksehir depending on performance targets of both the player and club.
"We are extremely happy with the arrival of Cengiz, a player with great technical ability," Roma sporting director Monchi added. "We are confident he will quickly adjust to his new surroundings and his quality and talent will be a valuable addition to our squad."
Roma have already signed Hector Moreno, Rick Karsdorp, Lorenzo Pellegrini and Maxime Gonalons this summer, while Mohamed Salah, Antonio Rudiger and Leandro Paredes are among those to have departed.