Sonia Gandhi and Rahul will represent Congress at the swearing-in ceremony of Narendra Modi as Prime Minister on Monday.
The Congress President had congratulated Modi on May 20 hours after he was elected leader of BJP Parliamentary Party and the NDA, thereby setting the stage for him to become Prime Minister.
Sonia is also the Chairperson of the Congress-led UPA.
Rahul, who is the Congress Vice President, had led the party in the Lok Sabha polls. Congress saw the worst debacle after remaining in office for ten years.