How 'Challengers' turned Zendaya and the cast into tennis stars, from strength training to 10,000-calorie diets

• Zendaya, Josh O'Connor, and Mike Faist star as tennis players in Luca Guadagnino's movie "Challengers."

• Tennis coach Brad Gilbert served as a consultant on the film and trained the stars.

• The actors spent hours playing tennis, watching tapes, and putting on muscle to look like pros.

Whether she's riding sandworms through the deserts of Arrakis, performing trapeze stunts as part of a circus act, or swinging through the air via harness with Spider-Man, Zendaya physically commits to her roles.

So it's no surprise that the 27-year-old superstar had a similarly laser-focused approach to her latest role as the headstrong Tashi Duncan, a tennis prodigy turned coach in Luca Guadagnino's steamy new sports drama "Challengers."

"Even though she's this big star, she's a real person and she's somebody that is really dedicated to her craft," Brad Gilbert, the film's tennis consultant, told Business Insider. "She has a lot of the same DNA as a tennis player, the focus and the grit, determination to do what she's doing and transform herself into the character."

In "Challengers," Tashi's beauty and dominance on the tennis court catch the attention of best friends Art Donaldson (Mike Faist) and Patrick Zweig (Josh O'Connor). A messy love triangle develops, with the two men becoming rivals as they compete for Tashi's affection. It comes to a head years later when Art, now married to Tashi, and Patrick, Tashi's ex-boyfriend, face off at a challenger tournament leading up to the US Open.

Competing at such a high level doesn't happen overnight for professional tennis players, who spend years sharpening their skills with coaches, trainers, nutritionists, and sports psychologists. So to convincingly play elite players, Zendaya, O'Connor, and Faist turned to Gilbert, who has coached players like Andy Roddick and Coco Gauff to championship wins at the US Open.

Zendaya, O'Connor, and Faist underwent physical transformations to look like tennis pros

Gilbert spent three months working with the actors during a period that Zendaya referred to as "summer camp" at a "Challengers" press conference attended by Business Insider.

Zendaya and Faist had two months of preparation before traveling to Boston to start filming "Challengers." Meanwhile, O'Connor had the least amount of time to get lean, as he was coming directly from filming another movie, "La Chimera."

When the trio did eventually link up during pre-production, they spent four hours exercising daily — two hours of tennis with Gilbert followed by gym time with strength and conditioning coach Bryan Doo.

Faist, coming off his breakout role as Riff in Steven Spielberg's 2021 remake of "West Side Story," was thin and needed to bulk up by eating 10,000 calories a day and following a diet.

Zendaya, who has previously joked about lacking upper body strength, put on muscle and could proudly show off her toned biceps by the time filming started.

"She's an unbelievably hard worker," Gilbert said of Zendaya. "She's incredibly humble and dedicated."

The trio studied players, watched live matches, and worked closely with their body doubles

While tennis balls were digitally added to the film during post-production, it was still essential for the actors to swing their racquets using the proper techniques of seasoned pros.

To achieve this, the actors studied players and watched plenty of tapes that Gilbert's wife, Kim Gilbert, sent them. But what may have helped Zendaya the most in transforming into Tashi was attending college matches.

"For her character, we only knew she was a killer on the court, so we had to develop her style,'' Gilbert explained.

Once Zendaya started viewing her training from a dancer's perspective, making each shot akin to choreography, she was able to mimic the footwork and nuanced movements of her tennis double. The actor refined her technique by rewatching footage of them side-by-side, to the point that her body double sparingly appears in the actual movie, according to Guadagnino.

"That kind of became my entryway into looking like a tennis player because I knew that at some point I wasn't going to be one, but I could fake it," Zendaya said during the press conference.

"I think Z got up to speed incredibly," Gilbert said. "There was CGI, and there was a ton of stuff that the team made happen, but the actors themselves did an incredible job in a short period of time."

Conquering Art's one-handed backhand was no easy task for Faist

In "Challengers," Faist's character is a champion pursuing a career milestone: winning all four Grand Slams. To restore Art's passion for the game, boost his confidence, and end his losing streak, Tashi enters him into a challenger event in New Rochelle.

Gilbert said that of the three main characters, Art had the most defined game in the script — a classic, graceful style modeled after Roger Federer and Pete Sampras.

Although Faist had experience playing tennis on a competitive level in high school, abandoning his two-handed backhand in favor of the one-handed technique used by the legends proved difficult. To master the shot, Gilbert sent Faist tapes of one-handed backhands so he could watch and mirror the style.

Patrick's unusual serve was inspired by a real tennis player, and O'Connor spent weeks learning how to hit a tweener

O'Connor's character is a washed-up tennis player who has a freewheeling technique and a peculiar serve that plays a key role in the final match between Patrick and Art.

Gilbert said that Patrick's serve was always meant to have a "pronounced hitch" in the script for "Challengers." In creating the move, Gilbert took inspiration from former tennis pro Jay Berger, whom he distinctly recalled having a "waggle."

While Tashi is critical of Patrick's serve, he still parades with unwavering confidence and swagger. Those traits are also on display when Patrick resorts to a flashy, between-the-legs trick shot known as a "tweener" during a US Open doubles match with Art.

Gilbert said that Guadagnino wanted the tweener to be Patrick's "signature point," and spent weeks helping O'Connor perfect the shot.

One day during practice, O'Connor hit a "one-in-a-million" tweener, lost his balance, fell into a wall, and cut his knee. Gilbert described it as "the greatest tweener winner ever," but also one that O'Connor wouldn't be able to replicate again. Worst of all, there were no cameras rolling to capture the moment.

"He has the memory that he did it this one time, but I was so bummed for him that we didn't have this on camera that he could show everybody," Gilbert said.

Thankfully for "Challengers" audiences, a little movie magic ultimately helped him nail it.

Read the original article on Business Insider