Southampton have signed Ghanaian centre-back Mohammed Salisu from Real Valladolid for a fee of £10.9m.
The highly-rated 21-year-old, who made 32 appearances for the Spanish side last term, has signed a four-year deal.
Southampton manager Ralph Hasenhuttl said: "This is an important signing for us. Mohammed is a player who fits our profile well."
This week Saints also completed the signing of Tottenham full-back Kyle Walker-Peters for around £12m.
Salisu said: "Southampton is a club with a very rich history in developing young players, so it is a very good club for me to develop my skills and to learn a lot as a young player."
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