Sai's character Anjali needed a certain body type.
A source close to Sai said it was important to gain weight for the role.
"When Sai heard the script, one thing that came to her mind was that her character Anjali is a pimp who used to be a prostitute. She is carefree and probably won't be in the best of shape. The additional weight gain helped her get the body language," said the source.
The Ghajini actress wanted to make her character look authentic.
"Love Sonia is a hard hitting film and is a very close representation of reality. I had to go through a lot of research to bring Anjali to life on screen without making her look caricature-ish. I gained weight to make the character look more authentic. The way it's shaped up, I think it was worth it," Sai said in a statement.
Directed by Tabrez Noorani, Love Sonia is produced by Tamasha Talkies, David Womark and Noorani.
Presented by Samraaj Talkies in association with India Take One Productions, Cinemantra Entertainment, Media Dynasty Consulting Group and Prime Focus Group, the film is slated to release on September 14.
Images: Sai Tamhankar on Instagram