Nayanthara, born and brought up as Diana Mariam Kurian, was a born Christian. She changed her name because of her foray into films.
She reportedly converted to Hinduism Sunday morning at the Arya Samaj Temple in Chennai, the sources said, adding she has retained her name Nayanthara.
Some see it as a step towards her impending marriage to actor-director Prabhu Deva who divorced his earlier wife, a Muslim and did not change her religion at the time of marriage.
Nayanthara is tightlipped. Asked about her marriage, she says: "No comments."
On Sunday morning, the actress reportedly headed straight to the Arya Samaj Temple on Waltax Road.
She went through all the religious processes as per the scriptures. All the procedures of 'Shuddhi Karma', a procedure involving Vedic purification, were meticulously followed, say the sources close to Arya Samaj.
They also added that a 'homan' or fire ritual was held where Nayantara chanted hymns and the Sankeerthan Mantra.
Incidentally, the members of Prabhu Deva's family are devotees of the Suttur Mutt in Mysore. His parents are devotees of Male Mahadeshwara Swamy.
The sources said Nayanthara left soon after the purification ceremony. A certificate of conversion to Hinduism was issued to her. The actress flew back to Kochi by an evening flight.
It is reported that her parents have expressed their opposition to Nayanthara's desire to convert to Hinduism.
Nayanthara's last film "Ramayana", directed by veteran director Bapu, was completed only a few days ago.
Nayanthara who plays Sita's role in the film became emotional on the last day of her shoot and even lay prostrate before all the elders in the unit, including the octogenarian director Bapu.
Nayanthara says her decision to convert to Hinduism is purely personal.
"Yes, I have become a Hindu and it's my own personal decision. I went through the entire ceremony with passion and conviction, " she is believed to have told a friend.
She sports a tattoo of Prabhu Deva on her body. The couple were also seen in some film related functions together.