Arsenal have announced the signing of 18-year-old centre-back William Saliba, who will begin his Gunners career next summer.
Saliba joins for a reported fee of £27million but will head back to Saint-Etienne on loan for the upcoming season.
Club president Roland Romeyer described it as an 'imperative condition' of the deal and insisted that it was also the youngster's preference.
The pursuit of Saliba has been a drawn-out process, prolonged by an attempt from rivals Tottenham Hotspur to hijack the deal earlier this month.
However, Arsenal have now officially won the race for the highly-promising Frenchman.
The lowdown on Saliba
It is a marker of the buzz surrounding Saliba that he has earned this big-money move after just 19 appearances at the senior level.
He played an important role in securing Saint-Etienne's qualification for the Europa League as they finished fourth.
His impressive displays had earned him a new five-year deal at Stade Geoffroy-Guichard, significantly boosting his value.
Saliba has been capped by his country at five separate youth levels, most recently making his debut for the U20s in March.
He has earned comparisons to compatriot Raphael Varane, a World Cup and Champions League winner.
Emery's view
Saliba's new manager Unai Emery was keen to point out that Arsenal had to beat off plenty of competition for his signature.
He is also confident that spending another year in France will prove a wise move, allowing the defender to gain more valuable experience.
"We're delighted William is joining us," he said. "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."
Questions remain over Arsenal transfer plans
Saliba is the second new arrival to be confirmed on Thursday after Dani Ceballos sealed his loan switch.
He is the club's third signing of the summer, with another hot prospect, Gabriel Martinelli, having joined at the beginning of the month.
Saliba's impact will be realised in the long-term but as yet, Arsenal have failed to recruit a potentially swift remedy for their defensive woes.
Vastly experienced centre-half Laurent Koscielny has gone on strike in the hope of engineering a move away from the club.
It remains to be seen whether Emery will back the likes of Rob Holding and Calum Chambers at the heart of his defence or demand further investment.
Elsewhere, negotiations with Celtic over left-back Kieran Tierney have reached an impasse after two bids were rejected.