Southampton have signed midfielder Mateus Fernandes from Sporting Lisbon for a fee in the region of £15m.
The Portugal Under-21 international joins the Saints on a five-year deal.
Fernandes played five times for Sporting's first team and spent last season on loan at Estoril, making 28 Primeira Liga appearances.
"I'm very happy to be here - it's a dream come true to come to England and play in the Premier League," the 20-year-old said.
"It's the best league in the world, in my opinion. It has the best coaches, the best players, the best teams.