Natalie Portman has opened up about her latest film, Fountain of Youth, where she stars alongside John Krasinski as siblings. The actress spoke exclusively to PEOPLE at the Los Angeles premiere hosted at the American Museum of Natural History.

The actress revealed that playing Krasinski's sister was a dream come true, especially since both of them had imagined what it would be like to have a sibling. Portman, an only child, and Krasinski, who has two older brothers, brought their imagination to their characters, making the experience even more enjoyable.

"It was so incredible to get to work with John. He's so funny. He's so kind, such a good actor and to play brother and sister was really fun because both of us, I think, had an imagination of what it might be like," Portman tells PEOPLE.

The film, directed by Guy Ritchie, follows treasure-hunting mastermind Purdue (Krasinski) and his estranged sister Charlotte Purdue (Portman) as they come together to pull off a global heist to find the mythological Fountain of Youth.

The film also stars Eiza González, Stanley Tucci, Laz Alonso, Arian Moayed, and more. Fountain of Youth debuts on Apple TV+ Friday, May 23.

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