Arsenal have completed the signing of William Sailba from Saint-Etienne.

The Gunners paid £27m for the 18-year-old, who will return to the Ligue 1 club on loan for the 2019/20 season.

"We're delighted William is joining us," head coach Unai Emery said in a statement.

"Many teams wanted him but he decided he wanted to come to us and be part of our future.

"He will stay in France next season for more experience and then we look forward to him joining our group."