CANNES, FRANCE - American actress Riley Keough, the granddaughter of Elvis Presley, made her directorial debut on Saturday (May 21) at the Cannes Film Festival where a biopic of the rock 'n' roll legend will also make its world premiere next week.

During a panel discussion with entertainment trade publication Variety, Keough, 32, spoke about her admiration for Australian film-maker Baz Luhrmann, who wrote and directed the upcoming Elvis.

"The first movie I ever watched in the theater and said I wanted to make movies was Moulin Rouge, I was 12. It was a real honour to know Baz was doing this movie (about Elvis)."

Luhrmann, 59, also wrote and directed jukebox film Moulin Rouge, starring Nicole Kidman and Ewan McGregor, in 2001.

Keough, whose acting credits include Mad Max: Fury Road (2015) and Magic Mike (2012), said that she had already watched Elvis together with her mother, Lisa Marie Presley, and her grandmother, Priscilla Presley - an experience she described as "very emotional".

"I started crying five minutes in and didn't stop. There's a lot of family trauma and generational trauma that started around then for our family. I felt honored they worked so hard to really get his essence, to feel his essence."

On Instagram, 76-year-old Priscilla - who was married to Elvis from 1967 to 1973 - said the film was "beautifully done", while Lisa Marie, 54, said it was "nothing short of spectacular".

The movie, which stars Austin Butler in the titular role, is said to cover the early part of Elvis's career. It also stars Tom Hanks as Elvis's manager, Colonel Tom Parker, and is set for a wider theatrical release in late June.

Though Keough has an extensive filmography as an indie film actress, she has always wanted to be a film director: "As a young child, I would make little movies with my friends. I would never act in them. Acting was something that I did want to do, but it came later … that was my original desire, to direct and write."

However, she did not expect to bring her directorial debut to a stage as prestigious as Cannes. Her film, War Pony, was co-directed with fellow first-time director, Gina Gammell. The coming-of-age story follows two young Native American boys from the Oglala-Lakota community growing up on a reservation in South Dakota.

"It just started with notes in our phone. We didn't really have a goal. … We certainly didn't think we were coming to Cannes."