Speaking outside Holles Street National Maternity Hospital yesterday afternoon, Ahern said he was sure Georgina would make "a great mam" and that her husband, Westlife band member Nicky Byrne, would be a great father.

Looking relaxed and happy in a navy cord jacket and bright shirt, Ahern embraced his son-in-law before posing for photographs.

Accompanying her father was bestselling author Cecilia Ahern and her partner David Keoghan. Loaded down with gifts for her sister, Cecilia said she was "very excited" at becoming an aunt and godmother.

The twins, named Jay and Rocco, were born two months prematurely by caesarian section early on Friday morning. Speaking to media outside the hospital earlier, Nicky Byrne said their early arrival was a shock.

"But she was in hospital for observation 24 hours beforehand and there was no distress, " he said, adding that the boys were making "good progress".

When asked whether the couple would be selling any photographs of the babies to a magazine, Byrne said he "wouldn't be discussing that".

A spokeswoman for the couple told the Sunday Tribune they hadn't sold any photographs and would be releasing images to the media "eventually".

Byrne also revealed that the couple had not known the sex of the children prior to their birth, but had chosen their unusual names because they both really liked them.

Asked what he thought of his grandchildren being called Rocco and Jay, the Taoiseach laughed and admitted, "They're different, that's for sure."