According to Arab News, the crown prince and Egypt's president will discuss inter-Arab cooperation as well the latest developments in the region.
They then oversaw the signing of a number of agreements between Saudi Arabia and Egypt.
Prince Mohammed bin Salman will hold a first-ever meeting on Monday with Egypt's Coptic Pope Tawadros II during his visit to Cairo.
On Nov. 4, Hariri announced that he was stepping down in a televised address from Riyadh, only to rescind it the following month after France intervened.
They also agreed on continuing to work together to counter regional interventions and attempts to sow division and rifts among the region's countries.
"The Egyptian president reaffirmed that the security of the Gulf is an integral part of Egyptian national security", the spokesman added.
President El Sisi welcomed Crown Prince Mohammed bin Salman on his first official visit to Egypt as heir to the throne.
Saudi Arabia has agreed to supply Egypt with crude oil for six months from the start of this year, Cairo's Minister of Petroleum Tariq Al-Mulla revealed.
Egypt's top court on Saturday dismissed all outstanding legal challenges to a deal transferring two Red Sea islands to Saudi Arabia, a day before a visit by its crown prince.
As Egypt tries to keep a lid on any internal unrest, it has sided firmly with Saudi Arabia on key foreign policy issues including the face-off between the Kingdom and its foe Iran.
While expressing support for the Saudi-led war in Yemen, Cairo has stopped short of full engagement and has instead settled for a less direct military-support role. Doha denies the charges.
Egypt is contributing $600 million to the $1.6 million project, while other funders include the Kuwait Fund for Arab Economic Development, the Arab Fund for Economic and Social Development and the Islamic Development Bank.