"Uncompromising in his patriotism, he possessed remarkable qualities of leadership and abundance of attributes of head and heart which made him command great respect among all those who came in his contact," Advani said.
The BJP leader said Thackeray never compromised with the things he believed in.
"I can only say that his demise today has left a gaping void in the country's politics which will not be easy to fill," the senior BJP leader added.
He hoped that there will be calm and people of Mumbai will observe all the ceremonies as the "great man deserved". Advani said he and other party leaders would attend Thackeray's funeral.
Thackeray died in his Mumbai house at 3.33pm following prolonged illness.