Turkey attempts to patch damaged relations with Germany
It comes amid a row over pro-Ankara rallies were cancelled in Germany ahead of a vote next month on changes to the constitution in Turkey.
Around 1.4 million Germans of Turkish descent all eligible to vote in the election, and generally back President Recep Tayyip Erdogan.
"I have a telephone call with the German chancellor at 3pm (12pm GMT)," Yildirim told a rally in the central Turkish province of Kirsehir where he was campaigning for a "Yes" vote in the 16 April referendum to boost the president's powers.
A number of pro-Ankara rallies and speeches in Germany were cancelled following bomb threats.
Relations between Berlin and Ankara have been fraught in recent years, in part due to Germany's criticism of Turkey's mass arrest of suspected critics.
Turkey meanwhile accused Germany of backing Kurdish separatists.
Agencies contibuted to this story.