Chelsea have announced their fourth and fifth new signings of the summer.
The young pair, both agred 18, arrive on free transfers having impressed at youth level for their previous clubs.
Versatile midfielder Matos appeared at both Under-18 and Under-21 level for Norwich last season, and is yet to make his bow in senior football.
Meanwhile, left winger Moreira made two appearances for Benfica and is part of the Portugal squad due to face England on Sunday in the European U21 Championship quarter-finals.
Luis Castro, who coached the Benfica B team last season, has previously described Moreira as having a “difficult” period in Lisbon.
He told Mais Futebol in April: “He has improved a lot. He has this street football style, but it is increasingly productive.
“He is managing to reconcile being entertaining, because he brings spectacle to the game, with better statistics. And he has a very particular characteristic, which is not normal for a player of his talents, which is the defensive component.
“He's a defensive animal and I don't see many wingers worldwide with Diego Moreira's defensive commitment.”
