Singh, 67, a Rajya Sabha MP, who had openly revolted against Chief Minister Bhupinder Singh Hooda, made his announcement of joining the BJP along with his supporters, two days after he was suspended from the party.
His close confidant Jagbir Malik, a former minister also joined the BJP along with him besides some other former MLAs.
"The path I have chosen for myself will help strengthen the BJP in Haryana in the next 15 years," Singh said.     

Singh and former CWC member Jagmeet Brar were recently suspended by Congress for "gross indiscipline" and "deliberately lowering the prestige of the party".
The veteran leader and former Haryana Finance Minister had openly revolted against Hooda and his quitting the ruling party, has come as another jolt to Congress in Haryana which has faced a series of desertions in the election year. Polls are due in October in the state.
Singh had earlier while hitting out at Hooda, alleged that, "Congress in Haryana is no longer the party it used to be. It has now become Hooda's Congress."

Singh had previously also alleged that Hooda had centralised powers and it was one of the reason why the Congress had fared poor in the Lok Sabha polls.
Congress managed to win only one seat out of total ten LS seats in the state.
Singh told Shah at the rally that he along with his supporters will ensure the party's victory in the upcoming assembly polls that will bring about a change in the state's polity.
A prominent leader from Haryana's Banger area had demanded that the chief minister should be changed so that Congress's prospects in the polls could improve. He had said that he would not fight the assembly polls under Hooda's leadership.
He had over the past one year openly criticised Hooda from several platforms for alleged "lopsided development" in the state.
Singh lost the 2009 Assembly polls to former chief minister Om Prakash Chautala from Uchana Kalan segment.
Earlier Hooda, when asked to comment if Singh's leaving the party would dent its prospects in the upcoming polls, had said that in a democratic set up every leader has the right to join any party.
The chief minister had said that Birender Singh also has right to join any party and this would not affect Congress in any manner.
In the election year, the Haryana Congress unit has been facing an exodus of leaders, some of whom have joined the BJP camp since the last Lok Sabha polls.
Prominent Congress leaders who have switched over to the saffron party include Rao Inderjit Singh, who had also been vocal against Hooda.
Rao, who was then a Congress MP from Gurgaon, severed his four-decade old ties with Congress and contested as BJP nominee from Gurgaon and retained his seat. He is now a minister in the Narendra Modi government.
Senior leader from Bhiwani region Dharambir also switched allegiance to BJP and is now a MP from Bhiwani-Mahendergarh seat.
Former Union minister Venod Sharma too ended his four- decade old ties with the Congress to float his own Jan Chetna Party.
Ramesh Kaushik, won the Sonepat Lok Sabha constituency on a BJP ticket after quitting Congress. Last week, four-time Congress MP Avtar Singh Bhadana also quit the party.

Latest News from State News Desk