Tejashwi took the four MLAs to the assembly in a car he himself drove, in a gesture that was rich in optics as well as symbolism.
The byelections are scheduled to be held on March 11.
The video showed the sloganeers flashing the victory sign near Alam's residence.
The National Democratic Alliance in Bihar which so far had BJP, JD-U and the LJP as its constituents will now have another dalit-centric party HAM as a member.
"In May 2014, the BJP won 282 Lok Sabha seats. In four years, BJP government is down to 271, losing its simple majority in Lok Sabha minus its allies - considering the fact that PM Modi has suspended Kirti Azad and virtually disowned their most truthful, fiercely independent Patna Sahib MP," Surjewala tweeted.
In a stunning blow to the BJP on Wednesday, the party lost bypolls to all the three Lok Sabha seats it contested, including its bastion Gorakhpur, and Phulpur in Uttar Pradesh, besides Araria in Bihar.
Minority conference organised by the JD-U turned out to be a poor show with few from the Muslim community attending it, exposing the falling credibility of Chief Minister Nitish Kumar as a secular leader, says M I Khan.
The young RJD leader is yet to earn the trust of the crowd and many senior party members believe he is no patch on his father.
The bypolls are termed as a 'rehearsal' for the 2019 Lok Sabha polls by CM Yogi Adityanath.
CM Yogi Adityanath said the BJP was getting widespread support from the people.
Nitish 'sent his emissary, Prashant Kishor, to me on five different occasions.' 'Kishor seemed to indicate that if I were to assure in writing my party's support to the JD-U, the latter would pull out of the BJP alliance and rejoin the Mahagathbandhan.' A revealing excerpt from Lalu Prasad Yadav's Gopalganj To Raisina: My Political Journey.