By Stephen Brown
BERLIN (Reuters) - German Chancellor Angela Merkel will host David Cameron and his wife and children at a castle outside Berlin at the weekend in a rare family get-together that she may hope will create the right mood to heal a growing rift between Britain and Europe.
Cameron, who warned this week that British support for the EU was "wafer thin", will spend the weekend with Merkel and her husband Joachim Sauer at Schloss Meseburg northwest of Berlin accompanied by his wife Samantha and their three children.
Spokesman Steffen Seibert was unable to recall any previous time that Merkel has hosted a leader's children. She and Sauer have no children of their own and are both serious scientists who like listening to Wagner operas and hiking.
"Don't worry, it will be an interesting experience for all those present," Seibert said. "You need have no concerns about the plans. Adults and children alike will have a lovely time."
Merkel, 58, tends to keep her personal life private, rarely appearing with Sauer in public, though they were photographed in bathing suits on an Easter break in Italy and papers ran shots of her playing with her nieces and nephews.
Asked why Merkel had turned the talks into a family gathering, Seibert said she and her husband had got to know the Camerons when they stayed at the British prime minister's official country residence, Chequers, in 2011.
The gathering "demonstrates how tight our friendship and partnership with Britain is", said Seibert.
The Camerons will arrive on Friday and Merkel and Cameron will hold wide-ranging talks early on Saturday that will naturally include Europe, he said.
Cameron's desire to roll back European Union powers and his plans for a referendum on Britain staying in the bloc if he wins a new term in 2015 were "no surprise" to Berlin, said Seibert.
Cameron said in an interview for several European media this week there was little support in Britain for an EU bureaucracy that he said "sometimes overreached itself" and needed reform.
Merkel's reaction to Cameron's speech in January setting out his plans on Europe was more restrained than that of some other EU leaders and she has been careful to stress that Britain is an important German ally, especially on free trade issues.
German lawmakers have long expressed frustration with Britain's semi-detached relationship with the EU, including Cameron's decision in 2009 to pull his Conservatives out of the centre-right bloc in the European Parliament to which Merkel's Christian Democrats belong.
(Additional reporting by Gernot Heller; Editing by Gareth Jones and Sonya Hepinstall)