Series star Sienna Miller talks starring opposite the Oscar winner in whale form and telling human stories about the climate crisis.

Sienna Miller informs Meryl Streep that she is the last humpback whale on Earth in EW's exclusive look (above) at Extrapolations, Scott Z. Burns' upcoming climate change drama.

The eight-episode series (out March 17) introduces a future where the cataclysmic effects of climate change have become embedded into our everyday lives. The interwoven stories — led by an ensemble cast that also includes Kit Harington, Daveed Diggs, Gemma Chan, David Schwimmer, Eiza González, Edward Norton, and Forest Whitaker, among others — explore the intimate, life-changing choices that must be made when the planet is changing faster than the population.

Miller and Streep's debut episode, "2046," presents an abysmal hereafter where animals, including tigers and orangutans, are extinct. Miller portrays Rebecca, an archivist who studies the extinctions and works to preserve the animals' memories, while Streep — without giving too much away — is not merely a whale per se, but Rebecca's late mother, Eve.

Sienna Miller and Meryl Streep (in whale form) on 'Extrapolations'
| Credit: Apple TV+

While an email from Burns containing an enticing P.S. that Streep would play her mother was enough for Miller to say yes to the project script unseen, it helped that the source material centered on a topic that she already cares deeply about.

"When you're dealing with such an enormous crisis of climate and also climate change denial — especially having lived in America throughout the last presidential reign, and having seen the documentaries, many of which Scott was involved with — there's a lot that can be said from watching documentaries and dealing with hard facts," Miller tells EW.

The climate crisis is "encroaching upon all of us," Miller warns, and she's inspired by the way the series presents the dire situation at hand through the "medium of human connection." It was a no-brainer to collaborate with Burns, who "really does walk the walk" when it comes to environmentalism, Miller says. "We spent time talking about cause and effect. Something I find consoling in some ways is that the Earth will repair itself irrespective of our behavior, as it has always done."

Sienna Miller
Sienna Miller on 'Extrapolations'
| Credit: Apple TV+

"The thing that motivates us as human beings is love and family," she says, adding that the series is "very much about love and what we should be fighting to preserve. There's levity in it and there's truthfulness in it. Any [project] set in the future that doesn't include an element of climate change is really not truthful." Miller hopes it inspires thought and conversation, "and that people feel galvanized to really look at the world we're leaving our children and try to affect change now, because we are up against the clock."

But, um, yes, Academy Award winner Streep voices a humpback whale. While recording the dialogue in a studio ahead of filming, Miller recalls, "I said to her, 'I can't believe it. Is there nothing you can't do? You're a whale now.' I mean, come on. She's heaven on earth, as you can imagine."

Extrapolations debuts March 17 on Apple TV+ with three episodes, followed by weekly episodes on Fridays until April 21.

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