Hezbollah chief Hassan Nasrallah will speak on Sunday for the first time since ministers from his party and its allies toppled the government of Saad Hariri, the Shiite group's television said.
The announcement comes a day after Mr Hariri, who was in the United States when the cabinet walkout took place, returned home and vowed to cooperate in forming a new government.
"The secretary general of Hezbollah, Hassan Nasrallah, will make an appearance on Sunday at 8.30 pm (1830 GMT). To comment on the latest developments," Al-Manar television said.
Hariri's government collapsed on Wednesday after the powerful Iranian-backed Hezbollah and its allies resigned in a dispute over a UN-backed probe into the 2005 murder of his father, ex-Premier Rafiq Hariri.
Shortly after meeting President Michel Sleiman on Friday, Mr Hariri said "my allies and I will participate in consultations (to name a new premier) and will fully cooperate with the president to form a new government in line with the requirements to maintain national unity."
The Western-backed Premier, after a week of talks in the United States, France and Turkey, said the collapse of his cabinet was "unprecedented in the history of Lebanese governments."
Hezbollah, Lebanon's most powerful armed faction, for months has been pressuring Hariri to reject the special tribunal for Lebanon, which is reportedly poised to indict high-ranking members of the party in the Hariri assassination.
The Shiite group has warned of grave repercussions should it be accused of the murder.
Although he did not specifically refer to the tribunal, Hariri made clear he would not cave in to pressure to reject the court.
He accused Hezbollah of refusing to make concessions while pressing him to "make personal and national sacrifices."
Hariri said his consultations abroad were aimed at "protecting Lebanon from sliding into the unknown."
"Some took advantage of the situation to . Put an end to the political truce" brokered by Saudi Arabia and Syria, he said, adding dialogue was the only way out of the current impasse.
"No one party in Lebanon can rule on its own," he said.
Sleiman, who declared the government a caretaker cabinet after the resignations, is to begin consultations with MPs on appointing a new Premier on Monday.
Turkey and France have been leading the way in efforts to prevent an outbreak of violence in the troubled West Asia country.
France, Lebanon's former colonial power, has proposed the creation of an international "contact group" similar to that of the Balkans in the 1990s to negotiate a settlement, a European diplomat in Beirut told AFP.
The French foreign ministry refused to confirm or deny the proposal.
Turkey, a Nato member seeking to position itself as a key broker in theWest Asia , has said it was ready to play "an active role" in helping end the crisis in Lebanon.
Turkish Prime Minister Recep Tayyip Erdogan said on Friday after meeting with Hariri that he was ready to contact regional heavyweights Syria and Iran among others.
And US ambassador to Lebanon Maura Connelly reiterated her country's unwavering support for the tribunal, urging Lebanon's feuding camps to exercise restraint.