Southampton have signed defender Tino Livramento from Chelsea on a five-year deal.
Livramento, 18, is the second teenager to join Southampton from Chelsea in the space of five days after the arrival of fellow defender Dynel Simeu.
Saints said: "Southampton Football Club is delighted to announce it has completed the signing of exciting young full-back Tino Livramento from Chelsea.
"A highly sought-after talent, Livramento arrives at St Mary's on a five-year contract, bolstering Ralph Hasenhuttl's squad ahead of the 2021/22 Premier League campaign."
Livramento is an England under-20 international and was included on Chelsea's bench last season in their Premier League win at Manchester City and the home defeat to Arsenal, both in May.
Saints boss Hasenhuttl said: "He's one of the best young players in his position in the country and there were a lot of clubs who were interested in signing him, but finally he chose to join us.
"I think he has made a very good choice, and this will be an excellent place for him to continue his development and hopefully reach his full potential."