Former Congress legislator K Lakshminarayanan joined the All India N.R. Congress (AINRC) in the presence of former Chief Minister and party founder N Rangasamy in Puducherry on Wednesday.
Mr Lakshminarayanan represented the Raj Bhavan constituency in the territorial Assembly on Congress ticket.
He however quit the Congress and the MLA post on February 21 just a day ahead of trust vote.
There was a spate of resignations by the then ruling Congress legislators and also by a legislator belonging to the DMK K Venkatesan culminating in the fall of Narayanasamy which led to the end of the Congress government on February 22.
The Union Territory goes to Assembly polls on April 6 to elect thirty MLAs.