Head coach Fernando Santos has called on the 34-year-old for the Euro 2020 qualifiers against Ukraine and Serbia, insisting he is the best player in the world right now.
As Europe's leading international scorer with 85 goals for Portugal, he is also Portugal's most experienced player with 154 caps.
"Cristiano is the best player in the world who returns to his team," Santos said, as per The Independent. "Any team gets stronger."
This marks the first call-up to the squad for the captain after since Russia 2018 and since he was accused of rape last year - which he has vehemently denied.
Portugal squad in full:
Goalkeepers: Beto, Jose Sa, Rui Patricio
Defenders: Joao Cancelo, Jose Fonte, Nelson Semedo, Ruben Dias, Mario Rui, Raphael Guerreiro
Midfielders: Danilo Pereira, Ruben Neves, William Carvalho, Bruno Fernandes, Joao Mario, Joao Moutinho, Pizzi
Forwards: Bernardo Silva, Goncalo Guedes, Rafa, Andre Silva, Cristiano Ronaldo, Diogo Jota, Dyego Sousa, Joao Felix
Ukraine are first up for the Selecao on March 22 with Serbia on March 25 in Lisbon.