Keerthy bagged the award for her role in the bilingual film "Mahanati".
Reacting to the big win, Keerthy posted a lengthy note on Twitter, thanking everyone for their wishes.
"First and foremost, I would like to thank each and every member from the press and media fraternity. They have been the early ones to strongly affirm that our film 'Mahanati' will get its due honours with their positive reviews and unconditional appreciations.
"I am overwhelmed with joyful elations and earnestly thank my producers Ashwini Dutt sir, Swapna Dutt, Priyanka Dutt, director Nag Ashwin, music director Mickey J Meyer, cinematographer Dani Sanchez Lopez, art director Kolla Avinash, production designer Sivam Rao... Every assistants in the above mentioned departments and all the other technicians who shed their sweat spending more time and energy nurturing this film," the post read.
She also thanked her co-stars including Dulquer Salmaan and Vijay Deverakonda.
"If not for my co-stars Rajendra Prasad sir, Dulquer Salmaan, Samantha Akkineni, Vijay Devarakonda and all my other artistes, 'Mahanati' would not be a complete film.
"The efforts of the technicians and actors commuted me into the world of the legendary Savitri Amma; whose blessings I believe was the strongest reason in getting accolades for me and my team. I am happy that the film has won three National Awards," she added.