Sienna Miller was taken aback by a phone call from 'Horizon' director Kevin Costner, reminiscing about their '90s heartthrob days.

Sienna Miller's career journey was sparked by a shocking phone call with Kevin Costner.

In an interview with Planet Chronicle Digital, Miller disclosed how she joined Costner's project, "Horizon: An American Saga," which was previously known as "American Sniper."

"I received a call from Kevin Costner, who wanted to discuss a project he was working on. I was ecstatic, as I had always been a fan of his work. He then sent me four scripts, which made me think it was for TV. However, it turned out to be for movies. We had a great conversation on Zoom, and I was thrilled to be working with such a talented actor. At the end of our chat, Kevin asked me a question that left me speechless: 'Will you go West with me?' I was overwhelmed with excitement and agreed to the opportunity."

"She remembered recalling, 'Yes, yes, I will go. I will go to the moon and back a million times,'" she said.

Since "Dances with Wolves," Miller has been a fan of Costner's and named two of her pet rabbits after characters in the movie.

She named one wolf after Cleopatra and another after Thumper from the film, along with Badger, Two Socks, and Cisco, as she told Planet Chronicle Digital.

"I was a huge fan of that movie," Miller added. "It broke my heart and I became very obsessed with Kevin from that moment forth."

Sienna Miller recounts the instance when Kevin Costner requested her participation in 'Horizon'.

Sam Worthington, known for his role in "Avatar," revealed what drew him to Costner's project.

"I enjoy collaborating with directors who push boundaries and strive for self-improvement in storytelling," Worthington, 47, stated to Planet Chronicle Digital. "On 'Avatar,' we employ a more conventional approach to filmmaking. However, it's not a plot-driven narrative."

"He has adopted a novelistic approach to the journey of these characters, particularly the central character, the town of Horizon. This method is unique and I find it impressive."

"I just like working with directors that take risks and are trying to challenge themselves in storytelling." — Sam Worthington

'HORIZON' Star Sam Worthington Discusses Kevin Costner's Message to America

Costner's storytelling in "Horizon" provides a broader perspective on the current state of the country, despite the film's focus on the West before and after the American Civil War.

"Worthington told Planet Chronicle Digital that he believes Kevin's story highlights the hope that America was founded on, and if there was hope in its formation, then there may be hope for its continuation, whether it's in the West or science fiction."

""If that's his message, I believe it's a fantastic message for the current America," he stated."

"I think that Kevin is telling a story that shows that there was a lot of hope in how America was formed." — Sam Worthington

With the successful production of his Western, Costner solidified his reputation as an excellent boss.

While filming the second installment of "Horizon," Miller was pregnant. The second film, "Horizon: American Saga," will be released on Aug. 16, while the first film, "Horizon: American Saga," will be released on June 28.

"Kevin was incredibly sweet to me," she confessed. "He kept bringing me snacks and drinks, even though I had already told him I hadn't shared my secret with many people. I found myself constantly eating to keep my nausea at bay. Whenever I was eating, I felt better. But there were still a few moments of nausea behind tents."

Filming was an opportunity for Worthington to learn from everyone on set, as Costner had assembled a cast with diverse backgrounds and experiences.

"He told Planet Chronicle Digital that he believes everyone is present for the right reasons to assist him in telling his story accurately. As a result, you gain insight into how they collaborate to achieve the best outcome for the boss."

In the Western saga, Frances Kittredge, portrayed by Miller, and Trent Gephart, played by Worthington, are joined by Luke Wilson, Abbey Lee, Jena Malone, and Giovanni Ribisi.

The four films directed by Costner, who also starred in "Horizon," were written by him.

Nearly 30 years ago, the 69-year-old actor deemed the saga a passion project and backed it with his own money.

"He previously stated in GQ magazine that he had $20 million of his own money invested in the movie. However, he clarified that this was not accurate, as he currently has approximately $38 million in the film. This is the correct amount."

With the release of the first "Horizon" film, Costner has shifted his focus solely onto the series, leaving behind his role as John Dutton in "Yellowstone."

He left due to the numerous uncertainties surrounding it.

He informed Planet Chronicle Digital that it was time for him to step away.

In 2025, Costner will release a new project on FOX Nation, following his previous hosting of "Yellowstone: One Fifty," which delves into the history of the national park.