The ambitious period romance also stars Ranveer Singh and Deepika Padukone.
"For me the film is a poetry in motion. That movie is poetic. It is beautiful.
Usually characters do not affect me but this film has emotionally exhausted me," the 32-year-old actress told PTI.
"I am mentally affected... As a character it is something I haven't experienced. There is so much emotional turmoil. It is a 17th century film and the most difficult film I have ever done," she said.
The national award-winning actress plays Kashibai, the first wife of Baji Rao (Ranveer), while Deepika will be seen in the role of Mastani, his second wife. Before "Bajirao" hits theatre, Priyanka will be seen playing sister to Ranveer in their upcoming film "Dil Dhadakne Do", which releases on June 5.
When asked if the sibling relationship affected their romantic side in "Bajirao", Priyanka said, "In 'Gunday' he (Ranveer) was my boyfriend. Sanjeev ji and Jaya ji, Aishwarya and Shah Rukh have played such characters where they played partners and then brother and sister. Now it is us. We are actors and our job is to act. We hope people like us," the "Mary Kom" star said.
The actress also praised Deepika, with whom she has done a special Lavani number in the film.
"It was great working with her (Deepika). If I had to do a film with someone then it would had to be with her," she said.
There have been reports that Priyanka will be a part of Omung Kumar's next film, a biopic on the slain Indian prisoner Sarabjit Singh.
"I am not offered that film yet... I am reading about it in newspapers," Priyanka said.
Priyanka's debut home production film “Madamji”, to be helmed by her “Fashion” director Madhur Bhandarkar, has been put on hold reportedly due to her date issues.
“We have put it on hold. There were lot of issues... A lot of back and forth happened.
“He (director Madhur Bhandarkar) was busy with ‘Calendar Girls' and I was busy with ‘Bajirao Mastani'. It is a great script and I hope I can pick it up some other time,” the actress said.