Arsenal have completed the signing of French centre-back William Saliba from St Etienne on a long-term contract, the Premier League club said on Thursday.
As part of the deal, Saliba will return to the Ligue 1 side next season on loan before heading to the Emirates Stadium in 2020.
No financial details were disclosed, but British media reports said the fee for the 18-year-old was about 27 million pounds ($33.62 million) to be paid in instalments.
"We're delighted William is joining us," Arsenal manager 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."