The star's fans rushed to congratulate the star, with one writing: "Congratulations king!"
As well as his football moments, social life and various commercial ventures, Ronaldo increasingly celebrates his growing family, sharing tender moments with his legions of followers.
Ronaldo took to Instagram to break the news and share a photo of the new happy family, including his eldest son Cristiano Jr.
This is Georgina Rodríguez's first child, while it's Cristiano Ronaldo's fourth.
Rodriguez, 22, was reportedly due to give birth around November 21 but went to hospital earlier today.
7.2 magnitude natural disaster strikes Iran-Iraq border region - USGS
The temblor was centred 32km southwest of Halabja, Iraq, near the northeastern border with Iran, the US Geological Survey said. Iranian provinces in the northwestern, western and central areas of the country were impacted, according to Iranian state TV.
While this is his first with girlfriend Rodriguez, this is his fourth, with twins named Eva Maria and Mateo from a surrogate and son named Cristiano Jr.
As with his first-born, Ronaldo is happy to show off his twin children and they regularly feature on both his Instagram and that of his girlfriend Georgina.
Soccer star Cristiano Ronaldo has announced that he is the father of a baby girl.
He wrote: "Alana Martina has just been born!"