The prime minister of Luxembourg is marrying his partner a year after the tiny, staunchly Roman Catholic nation's parliament approved a law allowing same-sex marriage.

Prime Minister Xavier Bettel at first said he wanted to have a very private wedding, but by Friday morning, he had already posted a picture of himself with Belgian partner Gauthier Destenay on his Twitter profile page. The official ceremony at Luxembourg City Hall is set for late Friday afternoon.

In 2010, Iceland's prime minister married her partner in what was believed to be the first same-sex wedding of a ruling government leader in Europe.

Bettel, a 42-year-old lawyer, heads the free-market DP liberals, who entered a coalition government with the Socialists and the Greens to end 34 years of Christian Democrat reign in Luxembourg.

On July 1, this nation of 520,000 will take over the presidency of the 28-nation European Union, giving Bettel major international exposure.

Shoehorned between Germany, France and Belgium, Luxembourg has been at the heart of European affairs since the founding of the EU in 1957. It was long seen as a picture of sedate bourgeois conservatism, yet it has become a major financial center, giving it clout well beyond its size.

Bettel has also reinvigorated the political scene with reforms. Last year, lawmakers overwhelmingly approved changes to allow people of the same sex to wed and to adopt children — part of the most fundamental revision of Luxembourg's laws on marriage since 1804.