"Ola John has extended his contract for another season," said Benfica, adding that the loan deal had gone through.
The 24-year-old has one international cap with the Netherlands had signed a five year deal with the Portuguese outfit when he joined from Twente.
Besiktas will have the opportunity to buy Talisca at the end of the loan period, Benfica added.. The 22-year-old had joined them in 2014 from his childhood club Bahia.