The beloved film "The Sisterhood of the Traveling Pants" celebrates its 20th anniversary, having first premiered on June 1, 2005. Based on the best-selling novels by Ann Brashares, the movie follows four lifelong best friends—Carmen (America Ferrera), Lena (Alexis Bledel), Bridget (Blake Lively), and Tibby (Amber Tamblyn)—who find a pair of jeans that magically fits them all perfectly. As they spend their first summer apart, the jeans become a symbol of their connection, and remarkably, the on-screen camaraderie blossomed into a genuine, lasting friendship among the four actresses in real life.

Director Ken Kwapis has shared insights into the casting process, emphasizing that he felt an immediate certainty upon meeting each of the four leads. Blake Lively's audition for the role of the free-spirited and athletic Bridget Vreeland was particularly notable. At just 16 years old and with no prior professional acting experience—as Kwapis recalled, "she came in without anything on her resume"—Lively demonstrated an "intuitive connection" to the character that secured her the part. This contrasted with her co-stars, Amber Tamblyn and Alexis Bledel, who were known for their roles in hit TV series, and America Ferrera, who had recently gained acclaim for the independent film "Real Women Have Curves." Kwapis also acknowledged that there were rumors of a different lineup for the cast, potentially including names like Hilary Duff, Olivia Wilde, Mischa Barton, and Kristin Kreuk, but he was confident in his final choices.

The role of Bridget Vreeland was one of the most challenging in the film. Her character is grappling with the recent suicide of her mother, a profound grief she attempts to mask with a sunny disposition while on a trip to Mexico. This internal turmoil leads to reckless behavior and a complex emotional journey. Kwapis highlighted the difficulty of this portrayal, especially for a first-time actor, and praised Lively for handling the "tough stuff" so beautifully, noting she had a "major emotional picture" to carry.

A significant challenge for Kwapis during pre-production was to cultivate a believable sense of lifelong friendship among the four actresses, who had never met before filming and shared relatively few scenes together, primarily at the beginning and end of the movie. To achieve this, Kwapis devised exercises to help them bond quickly. One such exercise involved sending the actresses to a thrift store with a small budget, instructing them to buy items in character and to advise each other, also in character. This helped them develop a shorthand and an organic rapport.

These efforts proved highly successful, not only translating into authentic on-screen chemistry but also fostering a deep and enduring real-life friendship among Ferrera, Bledel, Lively, and Tamblyn. This bond has lasted for two decades, a phenomenon Kwapis describes as "so amazing and it's particularly rare in show business," where intense relationships are often short-lived. The continued friendship of the cast is a special aspect of the film's legacy for both fans and the director.

"The Sisterhood of the Traveling Pants" became a cultural phenomenon, resonating strongly with audiences, particularly millennial teenage girls, due to its relatable storylines. Each of the four main characters navigates painful and transformative life events: Tibby forms an unlikely friendship with a young girl dying of Leukemia; Carmen confronts feelings of estrangement from her father and experiences racial prejudice; Lena learns to overcome her shyness and falls for someone her family disapproves of; and Bridget's journey through grief is described as an anchor for the film. These narratives explore themes of insecurity, self-discovery, love, and loss in ways that many viewers found authentic and moving.

Twenty years on, the film, with a runtime of 113 minutes, continues to be cherished and feels relevant. Director Ken Kwapis remains in touch with the cast and crew, occasionally participating in commemorative events, such as a screening in New York where he spoke alongside Amber Tamblyn. For those wishing to revisit the story or discover it for the first time, "The Sisterhood of the Traveling Pants" is available for streaming on platforms like AppleTV and Amazon Prime. There has also been discussion about a potential third film in the series, with some suggesting it might need to diverge from the book's later storylines to achieve success.