"RJD was in Congress-led United Progressive Alliance so their association is natural," Nitish Kumar told reporters here after attending an official function.
"The alliance of Congress-RJD and LJP is not a matter of worry," he said, responding to a controversy that it was a setback for him and JD-U, as he was keen on an alliance with the Congress after breaking up with the Bharatiya Janata Party in June this year.
Meanwhile, Rshtriya Janata Dal chief Lalu Prasad Friday left for Delhi to meet top Congress leaders, including Sonia Gandhi and Rahul Gandhi, to finalise the alliance, RJD leader Raghunath Jha said.
Lalu Prasad had said Wednesday that he would work hard for a strong secular formation to defeat communal forces in the 2014 general elections.
According to leaders close to Lalu Prasad, RJD has agreed to part with eight or 10 of 40 Bihar Lok Sabha seats for Congress, four for Ramvilas Paswan's Lok Janshakti Party, and two for the Left parties.
"RJD will always favour alliance with the Congress and LJP as our past experiences show good performance when we contested together, than when we contested alone," senior RJD leader Ram Chandra Purve said.