AAP leader Guggan Singh, who was fielded by the party from North West Delhi in this year's Lok Sabha polls, returned to the BJP on Monday.
He joined the saffron party in the presence of Union minister Prakash Javadekar and Delhi BJP chief Manoj Tiwari, ahead of the Assembly polls in the national capital.
Sources in the Aam Aadmi Party (AAP) claimed that Singh switched sides after realising that he would be denied a party ticket for the Assembly election, slated to be held early next year, from Bawana.
"He must have decided to part ways with the AAP after realising that he was not going to be fielded from Bawana," a senior party leader said.
Singh said it was his "fault" that he had left the BJP and accused AAP supremo Arvind Kejriwal of harbouring a low opinion about his MLAs.
"I was very hurt when I heard Kejriwal dubbing AAP MLAs as petty people at a meeting at his residence during the Lok Sabha polls," he said at a press briefing.
Singh added that he was feeling "suffocated" in the AAP as he was considered as a "BJP man" in the party circles.
The AAP accused him of levelling "false charges" on its leaders to "save his face" in an attempt to find "favour" with the BJP leadership.
Senior AAP leader and Delhi Deputy Chief Minister Manish Sisodia said Singh joining the BJP was a "poll season phenomenon".
"It is the election season. All this will keep happening," he said at a press conference and smiled when asked if it was a setback for his party.
Welcoming Singh in the BJP, Javadekar, who is the party's in-charge for the Delhi polls, said the saffron party will form the government in the national capital on its own and put an end to Kejriwal's "empire of lies".
Singh had quit the BJP and joined the AAP in July 2017 before the Bawana bypoll. His decision had followed AAP leader and Bawana MLA Ved Prakash quitting the party and joining the BJP.
Prakash was fielded by the BJP from Bawana, but he lost to the AAP candidate. He was also present when Singh joined the saffron party.
Singh, a Dalit leader in the outer Delhi areas, was fielded by the AAP from the North West Delhi seat in the Lok Sabha polls this year. He was defeated by BJP's Hans Raj Hans by a margin of over 5.9 lakh votes on the reserved seat.
Tiwari welcomed Singh in the BJP, saying "it's better late than never" and assured him that his respect and honour will be maintained in the party.
Former Union minister Vijay Goel and West Delhi BJP MP Parvesh Verma were also present at the press briefing.