Thapar, 26, was bragging about her family's wealth on the 'Heroine' set in northern India.
They lured her away by inviting her to a trip to Gorakhpur, a town close to the Nepali border where the film was being shot, the Daily Telegraph reported.
There they held her hostage and contacted her parents. The kidnappers told her mother they would force Thapar to star in pornography films, if the family didn't met their demands.
Her mother gave the kidnappers 60,000 rupees ($1,146.22). Determining that wasn't enough, they killed Thapar by strangling her to death and then beheaded her.
On their way back to Mumbai, the kidnappers dumped her torso in a water tank and threw her head out of a bus window.
They confessed to the murder after being found with Thapar's mobile phone SIM.
A detective on the case told The Daily Telegraph we are still investigating the case and both the accused along with a police team are visiting the crime spot. We have yet to recover the body.
She was strangulated in a hotel and her body was hacked into pieces and thrown in a water tank. They threw her head from a moving bus while traveling back to Mumbai, said the detective to the Daily Telegraph.
Jasiwal and Surin left for Mumbai in hopes of making it big in the Bollywood industry after Jasiwal's wife discovered their affair.
Thapar rose to fame after starring in the Bollywood hit 404: Error Not Found in 2011. The Indian horror movie centers around a medical facility where one of the rooms is haunted by a former student who committed suicide there.