The makers made the announcement about the espionage thriller on Wednesday, reported Variety.com.
While Dimple, 61, is yet to comment on it, celebrities from Bollywood have cheered her on.
Anil Kapoor, who starred in American series "24", called her casting "phenomenal", while filmmaker Anurag Kashyap tweeted wrote: "So cool... Dimple Kapadia in a Chris Nolan Film...Wow."
Film producer Guneet Monga sent in congratulations.
Dimple, who made her screen debut with 1973's Bollywood film "Bobby", is a National Award winner. She has proved her mettle in Indian cinema with an eclectic mix of parallel and commercial films like "Rudaali", "Krantiveer", "Dil Chahta Hai" and "Finding Fanny" among others.
Mumbai-based talent manager Purvi Lavingia Vats, who was instrumental in getting Ali Fazal a role in "Fast and Furious 7", says she pitched Dimple for the role to Nolan's casting team in Los Angeles.
"Dimple is a great and a wonderful person. She is the only Indian actor to be a part of this project as of now. They will be shooting the film in different countries, and India is one of them," Vats told .
"It took me a few months of convincing. But Dimple was up for it. It is something different for her, and it was an interesting process to make it all a reality," added Vats, who is focussed about getting more international exposure for Indian talent.
"Tenet" was so far being described as a "massive, innovative, action blockbuster", but plot specifics are under wraps, reported IndieWire.
Pattinson, John David Washington and Lea Seydoux are previously announced cast members.
Apart from Dimple, the new joinees in the film, to be distributed by Warner Bros. Pictures in theatres worldwide on July 17, 2020, include Aaron Taylor-Johnson, Kenneth Branagh, Clemence Poesy and Caine.
Pattinson had teased the scale of the film in an earlier interview to USA Today.
He had said: "I've been a little wary of doing big movies for years and years, but there's just something about Chris Nolan's stuff.
"He seems like the only director now who can do what is essentially a very personal, independent movie that has huge scale. I read the script and it's unreal."
Nolan's last film was "Dunkirk".
( With inputs from IANS )