In 2003, South Korea witnessed a golden age of television drama, and All In was at the forefront of that cultural tide. The SBS drama, set against the backdrop of a life of a legendary gambler, featured Lee Byung-hun, age 33, and Song Hye-kyo, 22, who had just burst onto the scene with "Autumn in My Heart."

As of KBZoom, their chemistry on-screen was "immediate and undeniable," especially during the Las Vegas shoot when the two shared a now-iconic kiss. The series debuted on January 15, 2003, at ratings of 35–40% and earned the pair the status of "the Romeo and Juliet of the gambling world."

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Off-screen, Lee's maturity and protective nature reportedly captivated Song. Despite efforts to keep their relationship private, paparazzi photos of secret meetings in Jeju Island and Las Vegas surfaced, confirming what fans had already suspected—a real-life romance had blossomed.

After the conclusion of the series, both agencies confirmed their relationship. For Song, it was her first high-profile romance, which elicited both admiration and criticism because of their 11-year age gap. The couple made numerous joint appearances together, including the 2003 SBS Drama Awards, where Lee won the Daesang.

As the souce explained, "Lee Byung-hun's mother even encouraged him to propose, hoping Song Hye-kyo would become part of the family." In spite of Song's hectic schedule shooting Full House, she found time to develop the relationship.

But cracks started to appear when their careers took off. Lee optioned Hollywood roles, while Song kept filming Korean dramas. Their brief time together fueled rumors of lifestyle and personality conflicts. Song's failure to attend the funeral of Lee's father in April 2004 created gossip about more serious problems.

By May 2004, the two confirmed their split, claiming "differences in personality and busy schedules." Behind the official pronouncements, insiders painted a wrenching breakup that left Song heartbroken. Friends reported she turned isolated and fought insomnia and mild depression.

Years later, in 2014, in an interview with Fuji TV, Song looked back and said, "The love that left the deepest impression on me was my first love."

Today, Song Hye-kyo has come back harder than ever. With highly praised roles in "Descendants of the Sun" and "The Glory," she remains one of the most respected actresses of Korea—a woman who turned heartbreak into transformation, an illustration of quiet strength and resilience.

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