Hungarian Prime Minister Viktor Orban, a fierce critic of Chancellor Angela Merkel's open-door refugee policy, will meet with former chancellor Helmut Kohl on Tuesday at his home in western Germany.
Kohl, the architect of German reunification in 1990, has been in poor health for several years and only rarely appears in public. He will welcome the Hungarian leader at his home in the city of Ludwigshafen around noon.
Orban has butted heads with Merkel over her insistence that EU member states honour their asylum commitments. The Hungarian premier has rejected her call for binding quotas and sealed off his country's border with a fence.
It is unclear why Orban and Kohl are meeting, but the visit has raised eyebrows in Berlin.
Some say it may be intended as a snub to Merkel, who was once Kohl's protege but later called for their Christian Democratic Party (CDU) to distance itself from him over a party financing scandal.
While already retired, Kohl voiced criticism of Merkel's policies in the eurozone debt crisis.
Merkel's Social Democrat (SPD) coalition partners and the opposition Greens have called on Kohl to act as a moderating influence on Orban in relation to his refugee policies.
"If others in Europe recognize that [Kohl,] the bloc's honorary citizen, is a good partner for conversation, then there's no harm in that," Peter Tauber, secretary general of the CDU, told public broadcaster ARD on Tuesday.