In a sudden development, liquor baron Vijay Mallya, Rajya Sabha MP from Karnataka, Saturday formally joined the Janata Dal(United) and was appointed as its senior National Vice-President.

Welcoming Mallya into the partyfold at the residence of former Chief Minister Ramakrishna Hegde, party president and Union Consumer Affairs and Food and Public Distribution Minister Sharad Yadav declared that his responsibilities would be announced soon.

Mallya, who successfully entered the Rajya Sabha as an Independent in the recent biennial elections, said he had joined the party following the advice of his mentor and "father figure" Hegde. He vowed to strive for the unity of the Janata Dal Parivar, he added.

Yadav said with the joining of Mallya, the strength of the party in Parliament rose to 12, ten in Lok Sabha and two in Rajya Sabha.

The announcement came Saturday morning after an extended meeting Yadav had with Hegde and Mallya Friday night. Even after Yadav left Mallya, was closetted with Hegde.

Yadav declined to comment on the merger move among the Janata Dal factions in Karnataka. He just said that JD(S) leader S R Bommai had been entrusted with the responsibility to work out the modalities.

Asked if he would meet former Prime Minister and JD(S) president H D Devegowda, he said,"I always meet him in the Parliament."