A memento is expected to be presented to Singh signed by all CWC Members and Union Ministers, sources said.
The dinner by Gandhi, who is also UPA Chairperson, comes two days before the announcement of results of Lok Sabha elections.
The Prime Minister would be demitting office on 17th May, a day after the Lok Sabha elections results are announced.
He had earlier this year announced his retirement, after a decade at the helm of two successive United Progressive Alliance (UPA) governments.
On the eve of his demitting office , the Prime Minister is to “address the people” in a farewell speech.
Congress leaders had always spoken of the relationship between the Prime Minister and Sonia Gandhi as an ideal division of labour, which saw perfect harmonization between the government and the party.
AICC has always maintained that there cannot be any better relationship between a party president and a Prime Minister and had often dismissed as “rumours and disinformation” reports of differences between the two.