Besides Mr Modi, former president APJ Abdul Kalam as well as a galaxy of educationists, political leaders and professionals will be in Kollam this week to felicitate Mata Amritanandamayi Devi.
Amma, as she is popularly known, was born into a struggling fisherman's family in Parayakadavu village in Kollam district on the Kerala coast on September 27, 1953. Her original name was Sudhamani Idamannel. She was only nine years old when she had to quit school after her mother fell ill. She began taking care of her seven siblings and doing household chores her mother could no longer handle.
By then, she had - surprisingly for her age - taken to meditating for long hours on the sea shore and also composing songs in Malayalam for Lord Krishna. She often sang some of them, attracting attention and admiration.
One of her responsibilities was to collect food scraps from others in the village, now known as Amritapuri, for her family's cows, a task that brought the girl face to face with the grinding poverty around her.
As she began growing up, she defied local sensibilities to embrace people who related their sufferings to her. It soon became her trademark, and she came to be known as the 'Hugging Saint'.
It was the beginning of a spiritual path that transformed the largely illiterate Sudhamani into a local lore, eventually earning for her the title "Amma" or Mother and a wide following first in Kerala and then across India.
In the last four decades, Amma, her ashram officials say, has physically hugged a whopping 33 million people - more than the combined population of Australia and Singapore.
Why does she do this?
"This is my inborn nature," she tells curious devotees. "The duty of a doctor is to treat patients. In the same way, my duty is to console those who are suffering."
Swami Amritaswarupananda Puri, one of her close aides, told IANS: "The only language Amma knows is Malayalam. But everyone who meets her is able to understand her spiritual message. This is because of the bonding she creates with the language of love."
From 1981 when the first ashram opened and six years later when she conducted her first programme, Amma's empire has grown enormously over the decades.
With millions of devotees, it now covers a wide spectrum: education, health, disaster work, aid projects and of course spirituality, in India and abroad.
Like other spiritual leaders, she has faced criticism. But a Communist newspaper in Kerala which once attacked her over alleged suspicious activities at her ashram not only retracted the story but issued an apology too.
The birthday celebrations, which began on Sunday, will peak on September 25-27 when Mr Modi, Mr Kalam, agriculture scientist MS Swaminathan, Nobel laureate Leland H Hartwell and many others will descend on the place.
So will hundreds of thousands of men and women who see Amma as a divine incarnation.