Ronaldo, who already has a son from a previous relationship, confirmed the news in a Facebook post following Portugal's defeat on penalties against Chile in the semi-final in Russia.
He will be allowed to return home to be with the twins and will therefore miss Portugal's third-place play-off match against the loser of the other semi-final between Mexico and Germany.
In his post on Facebook, Ronaldo expressed his gratitude to the Portuguese FA that he has been allowed to be with his new children.
Portugal's forward Cristiano Ronaldo takes part in a training session
Image credit: Getty Images
Ronaldo said: "I was in the service of the national team, as always, body and soul, even though my two sons were born.
"Unfortunately, we have not been able to achieve the main sporting objective that we wanted, but I am sure we will continue to give joy to the Portuguese.
"The President of the Portuguese Football Federation and the national picker have today had an attitude that has touched me and I will not forget.
"I'm very happy to finally be with my children for the first time."
The Portuguese FA also released a statement of their own, reciprocating Ronaldo's praise by commending the forward for wanting to play for the national team despite the birth of the twins.
"The President of the FPF and the National Team were informed before the Confederations Cup by the National Team captain, Cristiano Ronaldo, that he had been a father.
Portugal’s Cristiano Ronaldo with a mascot before the match against Chile
Image credit: Reuters
"The athlete, despite the birth of his children, made a point of being in the service of the National Team, in a gesture that we must underline and praise.
"The President of the FPF and the National Selector understand that if it is impossible to reach the goal of winning the Confederations Cup, they must release the athlete so that he can finally get to know his children."