The Indian dignitary is offering a special worship at the Janaki Temple when he arrives here on May 11 in course of his two-day State Visit to Nepal.
The khodasopachar ritual is a special worship to the deity which is based on mantras.
There is a tradition of performing this kind of special worship only on behalf the special guests visiting the temple, said Ram Tapeshwar Das Vaishnav, the Mahanta (priest) at the Janaki Temple.
According to him, before this only former Indian presidents Neelam Sanjeeva Reddy, Gyani Jail Singh and Pranab Mukherjee had performed special worship employing the khodasopachar ritual when they visited the temple.
Modi would become the first Prime Minister of India to perform the special puja using the khodasopachar ritual.
The khodasopachar ritual includes pancha aahuti, pancha tantra and five priests chanting the mantras.
This worship lasts for about an hour. Offerings of clothes, jewelries and ornamental items are made to the Hindu goddess Sita as part of the worship.