The details about her weight loss were revealed by her team in an Instagram post in which she is seen working out along with her fitness trainer.
"Guys, taking cues from #Kangana to workout, stay motivated and don't let the lethargy get to you. She has lost 5 kilos, long way to go!" read the caption of the workout video.
Earlier last month, Kangana's sister and manager Rangoli Chandel said that the actor had put on 20 kilos for the biographical drama based on the life of actor-turned-politician and former Tamil Nadu chief minister J. Jayalalithaa.
The 33-year-old actor will be essaying the role of Jayalalithaa in the flick.
The 'Tanu weds Manu' actor is currently in her hometown Manali and is practicing self-isolation.
( With inputs from ANI )