“To have interest from a few top clubs, to choose Southampton was sort of a no-brainer, "Livramento told the club's official website.
"They are a solid Premier League club and the manager was quite a big factor as to why I wanted to come here and why I wanted to play for Southampton.”
Hasenhuttl added: “He is 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."
He was a regular as the Blues finished second in Premier League 2 Division 1 last season, scoring three goals and providing 10 assists at Academy level.
He earned a place on the bench for two Premier League matches. He has also played for England's Under-20 team.