Kate Winslet reflects on 'Titanic' celebrating 25th anniversary: 'Just magical'

"Titanic" fans may be gearing up to celebrate the movie's 25th anniversary this month but Kate Winslet says the blockbuster film is "half my lifetime ago."

The actress, now 47, told "Good Morning America" on Monday that she turned 21 when starring alongside Leonardo DiCaprio in the James Cameron-directed 1997 film, which debuted in U.S. theaters Dec. 19, 1997.

Winslet, who eventually won an Oscar for "The Reader," called it "just magical" to have been in a movie that is as beloved today as the day it came out.

"It's amazing and incredible to have been part of something that, you know, is so steeped in nostalgia for people and still resonates with people in the way that it does," she said. "It's a huge, huge honor that people still love something that I was a part of all those years ago."

Winslet has reunited with Cameron for the filmmaker's long-awaited "Avatar" follow-up, "Avatar: The Way of Water." The sequel, coming 13 years after the first installment was released in 2009, hits U.S. theaters Dec. 16.

The film, also starring Sam Worthington, Zoe Saldaña, Sigourney Weaver and more, stars Winslet as Ronal. The "Mare of Easttown" star described her character as the "female warrior goddess leader of the Metkayina, the water tribe" on Pandora.

Winslet noted that Ronal is "the matriarch" of her clan and will "come up against" Saldaña's character, Neytiri, because "you can't have two matriarchs." She teased, "There are some sparks that fly."

"It was a wonderful role," she added. "My character is also pregnant, so she's this very kind of agile, capable, interesting, strong woman. I was really thrilled to be a part of it."

Winslet said Saldaña was "really generous in sharing with me the things that she had developed for her character," which helped make it so that it felt like Ronal "had always sort of been there -- we just hadn't actually met her yet."

Regarding how she learned to hold her breath underwater for upwards of seven minutes, Winslet said, "I couldn't believe what I was capable of."

"It was really fascinating, actually, to learn something new at a time in my life when, you know, I didn't necessarily think I was going to get to do that kind of thing," she continued. "So it was really cool."