And reports in his native Portugal claim the 25-year-old Russian may be expecting their child.
Newspaper Correio da Manha said she had been seen sporting a small bump - as well as showing off her diamond engagement ring.
A friend of the ex-Manchester United star told the paper: 'Cristiano loves being a father.
Although they weren't planning having a baby so soon, the truth is that nothing makes him happier than his son.
'And the birth of the boy awakened Irina's desire to become a mother.
'They had been talking about marriage. Cristiano wanted something very special and romantic, and on Valentine's Day he travelled to New York to surprise Irina.
'He asked her to marry her.' The friend said Ronaldo's mum Dolores wants the couple to marry in the footballer's home town of Funchal, on the Portuguese island of Madeira.
The friend said: 'At the moment there are lots of options open, but if it were down to Ronaldo's mother the wedding would be in Madeira.
