Prime Minister Narendra Modi addressing a record crowd of more than 50,000 Indian-Americans in Houston later this month will be a remarkable and momentous event, the Indian ambassador to the United States has said.

"I think Houston would be bigger and more momentous than all of these (overseas address of Modi as prime minister)," Harsh Vardhan Shringla told PTI in an interview.

Shringla was referring to the previous two major community address of Modi at the Madison Square Garden in 2014 in New York and San Jose in the Silicon Valley in 2016, where he spoke before a crowd of more than 20,000.

Personally involved in the planning of the mega event at the historic NRG Stadium in Houston on September 22, Shringla said this would be "historic".

So far, more than 50,000 Indian-Americans from across the US, but mostly from in and around Houston and Dallas area have registered for the third major public address of the prime minister in the country.

In 2015, Modi addressed an Indian diaspora audience of around 60,000 people at London's famous Wembley Stadium, where he was joined by then British prime minister David Cameroon.

"I think, it would be a very large event in the largest stadium in the city of Houston. It involves huge logistical and organizational challenges," the top diplomat said. "But I think the community is working assiduously to get this underway. We will see a remarkable event in by all standards."

Describing it as the "largest event" of its kind, the ambassador said it would be a bigger and momentous event as compared to all the previous overseas community events of the prime minister.

The mega event, billed as "Howdy Modi", has attracted great enthusiastic participation from Indian-American community. Organisers have closed the registration, once it crossed 50,000.

"There is huge amount of keenness among the community to welcome the prime minister to the United States, to welcome him to Texas and to listen to his vision," Shringla said.

From Houston, Modi will fly to New York to attend the annual session of the United Nations General Assembly.