His speech has been written by Pakistan's high commissioner to the UK, Wajid Shamsul Hasan, and was being given final touches by President Zardari. Both father and son reached Garhi Khuda Bux on Wednesday, ahead of the anniversary.
The move by President Zardari to hand over the mantle of the party to Bilawal Bhutto comes at a time when there is increasing criticism within the party over the failure of the government to arrest the killers of Benazir Bhutto.
In 2010, a UN report pointed fingers at a number of officials, both military and civilian, who hindered a proper investigation in the killing. The UN report suggested a more thorough inquiry which would take to task many of the figures identified.
"Ironically, the same people that Benazir Bhutto once identified as possibly behind attempts to have her eliminated are now the political allies of the government," points out Naheed Khan, a former personal secretary to Bhutto. Naheed Khan has since been ousted from the party by President Zardari.
Other changes that President Zardari is expected to make are announcing new members for the Central Executive Committee (CEC) of the party. The CEC takes most of the important decisions for the party.
In the past, Bilawal Bhutto has made speeches abroad but for the first time he will speak at a political rally in Pakistan.