Arsenal have signed France under-20 midfielder Matteo Guendouzi from Lorient in a deal reportedly worth £7 million.
The club announced the signing on Wednesday, with Guendouzi reported to have signed a four-year deal.
Guendouzi, 19, is regarded as one of the most promising central midfielders in France and is viewed as a signing for the future at Arsenal, but head coach Unai Emery indicated that he expects Guendouzi to fight for a first-team place right away.
"We are delighted Matteo is joining us," Emery said in a statement. "He is a talented young player and a lot of clubs were interested in him. He has big potential and gained good first-team experience last season with Lorient. He wants to learn and improve and will be an important part of our first-team squad."
Guendouzi said he is "immensely proud" to join Arsenal and said he has wanted to play for the club since he was a child.
"My hope is to become a top player here at Arsenal," he said. "A lot of great players have played here. I want to become part of the club's history and to achieve great things here.
"I want to win titles, titles, titles. I want to establish myself here, which would be amazing. Winning silverware, as I said, is very important to me and winning things here at Arsenal would be incredible."
Guendouzi broke into the Lorient side in the 2016-17 season, when he made nine Ligue 1 appearances, and he made 20 appearances last season.
He is known for his vision and passing ability as a deeper-lying playmaker but also has the pace and ball control to drive forward as a box-to-box player.
His arrival at the Emirates comes after Arsenal missed out on another top French prospect in Yacine Adli, who chose to remain at Paris Saint-Germain.
He is Arsenal's fifth signing of the summer after a deal for Sampdoria midfielder Lucas Torreira was completed on Tuesday.
Meanwhile, Arsenal have also signed another talented teenage prospect to their academy in 16-year-old striker Sam Greenwood.
The former Sunderland player posted a photo on Instagram signing his deal, writing that "today is the start of a new chapter in my life."