President Muhammadu Buhari and former President Olusegun Obasanjo met in Addis Ababa, Ethiopia, at the opening session of the 30th African Union Summit.
They both shook hands and talked for about two minutes.
A former head of state, General Abdulsalami Abubakar, later joined Buhari and Obasanjo for a snapshot.
Obasanjo had last week written a damning latter to Buhari, advising his against seeking reelection in 2019.
The former president had accused Buhari of nepotism and failure to revive the economy, among other accusations.