Thackeray said that though Bachchan has become a superstar in Mumbai but his heart is more inclined towards Uttar Pradesh than Maharashtra.
"Though he has become a star in Mumbai, his interest is in Uttar Pradesh. That is why he was trying to be an ambassador of UP rather than Maharashtra," Thackeray said at a function in Dharavi on Friday night.
He said that Bachchan was behaving as if he was an ambassador of UP rather than Maharashtra and said his loyalty was more towards UP than Maharashtra.
"That is why though he achieved everything in Mumbai, when it came to elections, Amitabh chose UP," he added.
Earlier, Thackeray received flak from political parties, for opposing 'Chhath Puja', for hurting the religious sentiments of people from Bihar and Uttar Pradesh.
He had recently objected to celebration of Uttar Bharatiya Diwas and Chhath Puja in Maharashtra.
Meanwhile, Congress spokesman Sanjay Nirupam termed Raj Thackeray's comments on Amitabh Bachchan as a "foolish statement" that doesn't merit any reaction.
"If people like Madhu Limaye who is basically from Maharashtra can contest elections in Bihar what prevents Bachchan from exercising his choice," Nirupam asked.
Raj is making such statements "only to snatch the Marathi voters from Shiv Sena", said Nirupam.