Congress leader Ghulam Nabi Azad is likely to represent the party at Rashtriya Janata Dal supremo Lalu Prasad Yadav's rally in Patna on Sunday.
Sources said the Congress supports the RJD and its rally and will be adequately represented, but the Gandhis are unlikely to attend it.
"The Congress supports the RJD and the leader of opposition in Rajya Sabha Ghulam Nabi Azad will be attending the August 27 rally of Lalu Prasad in Patna," said a senior party leader.
Congress vice president Rahul Gandhi had earlier indicated that he might be present at the Patna rally as Lalu has been a long-time friend and supporter of the Gandhis.
Their presence at his rally, however, may affect its prospects as Lalu and his son are embroiled in cases of corruption, analysts said.
Lalu is attempting a major show of strength after he was ousted from the Bihar government with the Janata Dal-United moving out of the grand alliance and joining back the National Democratic Alliance fold and the government with the Bharatiya Janata Party.
Earlier in the day, Lalu said West Bengal Chief Minister Mamata Banerjee and rebel JD-U leader Sharad Yadav would attend his rally in Patna on August 27 and Mayawati's absence from the event was not a 'setback'.
"I had a talk with Mayawati. She said senior BSP (Bahujan Samaj Party) leader Satish Mishra would come for the rally," he told reporters.
The RJD chief said senior Congress leaders Ghulam Nabi Azad and C P Joshi would also attend the rally with a message from Congress president Sonia Gandhi.
Asked about the chances of Congress vice-president Rahul Gandhi attending the event, Lalu said, "He could also be there."
He also claimed that Trinamool Congress supremo Mamata Banerjee and rebel JD-U leader Sharad Yadav would be on the dais that day.
At the time of announcing the 'BJP Bhagao Rally' (oust Bharatiya Janata Party rally) at the Gandhi Maidan in Patna, Lalu had boasted of bringing Mayawati and Samajwadi Party president Akhilesh Yadav together on one platform, which would mean the 'end of the match for the BJP in the 2019 Lok Sabha polls'.
Back then, JD-U chief Nitish Kumar was in the Grand Alliance, also comprising the RJD and the Congress, and Lalu, while heralding his coming together with Kumar in Bihar, had said joining hands by the SP and the BSP -- the two arch rivals in Uttar Pradesh -- would spell doom for the BJP in the next general election.
Asked about Kumar's and JD-U principal general secretary K C Tyagi's comments that if Sharad Yadav attends the rally against the party line, he would lose his Rajya Sabha membership, Lalu claimed that there was no such provision.
"Is there any provision like this in any party?...Political party leaders attend rallies organised by others...it does not come under the anti-defection law," he said.
Lalu further said, "Sharad Yadav represents the true JD-U."
Sharad Yadav, who had attended a parallel 'Jan Adalat' meeting, instead of attending the JD-U national executive meeting on Saturday, had asserted, "Mahagathbandhan jaari hai (the Grand Alliance is continuing)."
The RJD chief is criss-crossing the state to mobilise people for the August 27 rally, which he has claimed would be a major occasion to bring together the secular forces on one platform against the BJP ahead of the 2019 polls.