Aamir said: "Rajeshji is one of the biggest stars that India has seen. He will always be remembered by every Indian with a lot of love. He will be remembered for the joy, happiness and romance that he brought into our lives through his work. My heartfelt condolences to Dimpleji, Twinkle, and to all the members of the family."
Shah Rukh tweeted: "To live with intention & walk to the edge. Play with abandon, choose with no regret. Smiled & made us do the same. Sir, u defined our era. RIP.
"Mom & me use to sit & watch Mr Khanna's films back to back. Whenever life felt tough you made us feel how love could change it all. Will miss u."
Speaking via Twitter, producer-director Karan Johar said: "The magic...the mannerism...the mania of Rajesh Khanna is inscribed in every archive of Indian cinema...forever....RIP SIR!!!"
Khanna made his film debut in 1966 with Aakhri Khat. He was hailed as India's first superstar after scoring 15 consecutive solo hits between 1969 and 1972, including Aradhana, Haathi Mere Saathi, Anand and Amar Prem.
Amitabh Bachchan, Abhishek Bachchan, Shah Rukh Khan, Rishi Kapoor and Shabana Azmi are among the stars who have arrived at Rajesh Khanna's residence to pay their respects to the late star.
Khanna will be cremated tomorrow (July 19) at 11.30pm.