Coach Fernando Santos had initially said that a mutual decision had been made to give Ronaldo a rest following his move from Real Madrid to Juventus but had been ambiguous about the player's future when questioned in November.
Portugal continued to flourish without Ronaldo, winning their Nations League group against Poland and Italy with a game to spare to qualify for the final four-team tournament which the country will host in June.
However, any doubts about his future were removed when Ronaldo's name was among 25 read by Santos during a news conference for the Euro 2020 qualifiers against Ukraine and Serbia
"Cristiano is the best player in the world and is returning to his team," said Santos. "Any team is stronger with him."
Portugal host Serbia in Lisbon on March 22 and Ukraine three days later.
(Writing by Brian Homewood; Editing by Toby Chopra)
