Arsenal have signed Fabio Vieira from Porto in a 40m euros (£34.2m) deal.
“I am very excited that we have identified and signed such a special talent,” said Mikel Arteta. “Fabio is a very creative player that will bring high quality and versatility to our attacking play.”
Vieira was voted player of the tournament at last year’s European Under-21 Championship and scored six goals and 14 assists in 27 Primeira Liga games last season, helping Porto claim the title.