The Hamas government in Gaza confirmed on Thursday that the movement's politburo chief Khaled Meshaal was due in the coastal territory on Friday to celebrate Hamas's 25th anniversary.
The trip is set to be a historic one for Meshaal, who was born in the West Bank but has not visited the Palestinian territories since he went into exile after the 1967 Six-Day War.
He had been due to visit Gaza at the start of the year, but the trip never happened.
Hamas "announces the visit of Khaled Meshaal, head of the political bureau, tomorrow December 7, to participate in the celebration of the movement's 25th anniversary," Hamas spokesman Sami Abu Zuhri said in a statement.
During the visit, Meshaal will meet members of different Palestinian movements and residents of Gaza, "as well as representatives of the families of martyrs, prisoners and those injured in the last Israeli aggression against Gaza," the statement added.
The visit, Abu Zuhri added, was "a fruit of the victory of the resistance over the occupation."
Meshaal's trip comes after a ceasefire that ended eight days of conflict between Israel and Gaza militant groups.
The violence began on November 14, with Israel's targeted killing of Hamas military commander Ahmed Jaabari, and left 174 Palestinians dead, including more than 100 civilians, as well as six Israelis -- four civilians and two soldiers.
Hamas marks its official anniversary on December 14, but celebrations are set to begin earlier with a major rally on Saturday, when Meshaal is expected to speak.
Founded in 1987 shortly after the beginning of the first intifada, or uprising, against Israel's occupation of the West Bank and Gaza Strip, Hamas was inspired by Egypt's Muslim Brotherhood.
Its charter calls for the eventual destruction of Israel and the establishment of an Islamic state on the pre-1948 borders of the British Palestine Mandate.
In 2006, Hamas won a landslide victory in Palestinian elections, routing the long-dominant Fatah party of president Mahmud Abbas, and took over Gaza in June 2007 after months of factional unrest.