Priyanka, 33, who joined the micro-blogging site in 2009 and is one of the most popular Indian celebrities online, made a special video to share her excitement.
"Thank u guys for the love!! #3MillionOnInstagram #11millionOnTwitter so Grateful!," the "Mary Kom" star tweeted along with the video link.
"11 million on twitter, 3 million on Instagram. Thank you so much. I truly feel very very loved... Very excited," she said in the video.
Priyanka is gearing up for the US premiere of her debut American TV series "Quantico" that will be telecasted in India from October 3.
The "Gunday" star is also working on Sanjay Leela Bhansali's love saga "Bajirao Mastani" in which she is essaying the role of Peshwa Baji Rao's first wife Kashi Bai.
The film is slated for December 18 release.