Saad Hariri arrived in Egypt on Tuesday for talks with the Egyptian president as he prepares to return to Lebanon after resigning as prime minister earlier this month.
Mr Hariri had been in Paris since Saturday when he met French president Emmanuel Macron. He has said he would return to Lebanon by Wednesday for the country's Independence Day celebrations.
In his surprise resignation announced from Riyadh, Mr Hariri blamed Iran for its overbearing influence on his country and said he feared an assassination attempt.
Mr Hariri arrived at Cairo International Airport, where he was received by Egypt's health minister, the Lebanese ambassador to Cairo and Egypt's ambassador to Beirut, his press office said.
He went immediately to the presidential palace to meet Abdel Fattah El Sisi. A message on Mr Hariri's Twitter account said the meeting would be followed by a dinner in his honour.
Minutes after Mr Hariri landed in Cairo, small groups of supporters took to the streets of central Beirut in noisy convoys, honking, cheering and waving flags with the colours of the premier's Future Movement, AFP reported.
Mr Hariri's visit to Cairo follows two weeks of uncertainty after he announced his resignation. Saudi Arabia has denied accusations that it coerced him into standing down in response to the growing influence of Hizbollah in Lebanon. The Iran-funded militant group are the strongest military force in the country and have members in the coalition government.
Mr El Sisi has sought to defuse the tensions between Saudi Arabia, Hizbollah and its Iranian patrons.
Mr El Sisi's office said he received a phone call from Lebanese president Michel Aoun, a Hizbollah ally, in which they discussed "the importance of preserving Lebanon's stability and elevating Lebanon's national interests."
Speaking after talks in Paris on Saturday with Mr Macron, who is also seeking to broker a way out of the crisis, Mr Hariri said he would "make known my position" once back in Beirut.
Mr Aoun has refused to accept Mr Hariri's resignation while he remains abroad.
Mr Hariri - whose father, former prime minister Rafiq Hariri, was killed in a 2005 car bombing blamed on Hizbollah - took over last year as head of a shaky national unity government which includes the powerful Shiite movement.
Saudi Arabia's Foreign Minister Adel al-Jubeir meanwhile insisted from Madrid on Friday that "unless Hezbollah disarms and becomes a political party, Lebanon will be held hostage by Hizbollah and, by extension, Iran".
Mr Hariri's resignation was widely seen as an escalation of the battle for influence between Saudi Arabia and Iran, which back opposing sides in the conflicts in Syria and Yemen.
Riyadh on Saturday recalled its ambassador to Berlin in protest at comments by Germany's Foreign Minister Sigmar Gabriel which were interpreted as a suggestion that Mr Hariri acted under Saudi orders.
France, which held mandate power over Lebanon for the first half of the 20th century, plans to bring together international support for the country, depending on how the situation develops.
The French president has also telephoned his counterparts in the US and Egypt, as well as the Saudi Crown Prince Mohammed Bin Salman and UN Secretary-General Antonio Guterres to discuss "the situation in the Middle East".
He and Mr Trump "agreed on the need to work with allies to counter Hezbollah's and Iran's destabilising activities in the region", according to a White House statement Saturday.
Ahead of Mr Hariri's departure, Mr Aoun welcomed the trip to Paris, expressing hope it was the "start of a solution".
"If Mr Hariri speaks from France, I would consider that he speaks freely," Aoun said.
"But his resignation must be presented in Lebanon, and he will have to remain there until the formation of the new government."
* With reporting from Agence France-Presse, Associated Press and Reuters