Byrne proposed to Georgina Ahern in a pub

More than 200 fans gathered outside the registry office in Wicklow, south of Dublin, as Byrne, dressed in blue jeans and wearing a red baseball cap, married Georgina Ahern.

On Saturday the pair will have a church wedding in France, followed by a reception at the famous Chateau D'Esclimont near Paris.

Under French law, the couple have to have a civil ceremony beforehand.

It was reported that Byrne and Ahern arrived at the registry office separately in order to protect a $1m (�622,000) deal with celebrity magazine Hello, which will publish photos of this weekend's ceremony.

Byrne proposed to Ahern in a pub in December.

The Irish prime minister's other daughter, journalism graduate Cecilia, also recently hit the headlines after securing a $1m (�622,000) book deal for her debut novel and its follow-up.

Westlife, one of the most popular boybands in the UK charts, are releasing a new single, Hey Whatever, in September.