The 17-year-old goalkeeper has started training at Melwood and will playing for the club’s academy teams and will be also working with the Reds’ senior team.
The teenager won the FIFA U17 World Cup on home soil last November with Brazil.
Liverpool’s head of goalkeeping John Achterberg told the club’s official website about Pitaluga: “I saw him for the first time in the World Cup squad. You’re checking all the goalies and looking at the ages.
“You see that he was in the World Cup squad one year younger than the rest of the squad, then you think that’s worth a look because normally you have two goalkeepers of the same age, but if you have someone who is a year younger you think he may have some good attributes.
“He was at Fluminense; we got some games to look at, all the other goalie coaches also look at it Jack [Robinson] and the Academy coaches Mark [Morris] and Taff [Neil Edwards]. And, of course, I speak to the gaffer and the rest of the coaching department here.
“In Fluminense we had Allan [on loan], so I spoke to Julian [Ward, loan pathways and football partnerships manager] if he saw a little bit of him in training there. He saw him too and was also positive.
“I asked Ali to speak to his brother to see how it goes and how he is doing. Ali spoke to his brother and Ali went training there. We saw a little bit from the training and the games he was playing for the reserves in Brazil.
“He was already 16 playing in the reserve team there so you also think, they trust him to play already in the reserves at 16.”