Reacting to Tejashwi Yadav's response, Mr Sinha said, "I get a lot of affection and warmth from RJD chief Lalu Yadav and his family... and it is an open secret how much respect I enjoy from the RJD-Congress combine these days. He added that he would take an "appropriate decision in the near future".
Speculation about Shatrughan Sinha started after he chose to attend the Iftar party hosted by Tejashwi Yadav yesterday, instead of one hosted by ally Janata Dal United.
Asked why he skipped the JD(U)'s function, the lawmaker from Patna Sahib claimed he did not have knowledge of it. Tejashwi Yadav's father Lalu Yadav, he said, was a "longtime friend" and added that he was "delighted to be among my family friends".
The 71-year-old dismissed the possibility of his presence at the rival function generating bitterness between the allies. "Iftar only sweetens relationships," he said.
His move, however, irked leaders of his own party in Bihar. State BJP chief Nityanand Rai threatened action against the actor-turned-politician, saying "his time has come near".
Mr Sinha, once one of the key leaders of the Bihar, was seen as disgruntled after his frequent criticism of his party and Prime Minister Narendra Modi. His closeness to Yashwant Sinha, the BJP veteran who recently quit the party, has reinforced the perception. But so far, the BJP has not taken any action against him.
Critics have said Mr Singh's frequent outbursts are a ploy to draw attention by a sidelined leader, to which, Mr Sinha said says he was only "trying to show them (the party) the mirror".
In January, parts of the actor's Juhu home were razed by civic officials during a demolition drive. Mr Sinha said it was possible that he was being targeted for the stands he has taken.
On Sunday, Tejashwi Yadav had issued an open invitation to Union minister Upendra Kushwaha after he skipped a "unity dinner" hosted by the BJP in Patna. The absence was seen as deliberate, since Mr Kushwaha reportedly has misgivings about his treatment by the BJP. The leader who heads his own regional party, is said to feel sidelined to favour Nitish Kumar.
But Mr Kushwaha swiftly turned down Tejashwi Yadav's invitation, saying he is part of the NDA and will remain so.