"Egyptian people won't forget the historical contributions of King Abdullah Bin Abdul Aziz Al Saud towards Egypt. These contributions expressed his wiseness and deep faith in Arab solidarity," Sisi said in a statement issued early today.
Sisi has decided to cut short his visit to Davos in Switzerland to attend the royal funeral which is expected to take place today, an official source said.
He had been in Switzerland since Wednesday to participate in the World Economic Forum.
Abdullah was the first head of state to visit Cairo after Sisi's election win last May. The Egyptian leader in August last year reciprocated with a trip to the Saudi Red Sea city of Jeddah for talks with Abdullah.