Niger's President Mohamed Bazoum touched down in the Chadian capital N'Djamena on Thursday, a day before the funeral of the late Chadian president Idriss Déby.
Déby died after sustaining injuries on the front lines against rebels, the army said Tuesday.
The late Chadian President's funeral ceremony is slated for April 23, at the Place de la Nation in the capital.
The ceremony will then move to the Grand Mosque also in N'Djamena before the mortal remains are taken to Amdjarass city for burial.
Already, the Guinean head of state Alpha Condé and Mali's interim president Bah Ndaw are in N'Djamena for the funeral ceremony.
Other presidents are expected Thursday night and Friday morning.
The death of President Déby, who's been in power for 30 years, has opened a period of uncertainty for Chad.
The Central African nation is threatened by the rebellion and also within the regime.