"I had made this commitment to Balasaheb that I would make a Shiv Sainik the state's Chief Minister. I vow to fulfil that promise," Thackeray said amidst thunderous applause at a meeting of top party leaders, activists and aspiring candidates.
He said the saffron flag of Shiv Sena should be unfurled atop the Maharashtra legislature building in south Mumbai. The Shiv Sena and the BJP had ruled as a combine between 1995 and 1999 with Manohar Joshi and Narayan Rane as the Chief Ministers.
However, seeking to allay apprehensions in any quarters, Thackeray quickly added that the alliance with the BJP for the October 21 Assembly elections would happen and shall be announced "very soon".
"If the alliance materialises, we shall not backstab... We shall speak out openly," Thackeray said, adding that the party would strengthen the alliance candidates all over the state.
The Sena has been seeking a 50:50 ratio with both BJP and Sena contesting 135 seats each and leaving the remaining 18 seats in the 288-member House to the smaller allies.
There has been a clamour from within the party for Thackeray to take the political plunge and head the state's reins amidst political speculation that his son Aditya Thackeray may contest the Assembly elections and the BJP could offer the post of Deputy Chief Minister to Sena.
A couple of days ago, a seat sharing formula had come from the BJP circles whereby it would contest 144 seats, share 126 with Shiv Sena and allot the rest to other allies, but the Sena has not reacted to this yet.
Sena sources said the final figures would be jointly announced by the leaders of both parties and everything else was pure guesswork.
The 288-member Maharashtra Assembly will go to the polls on October 21 while the results will be declared on October 24.
( With inputs from IANS )