Reese Witherspoon Celebrates 15th Anniversary of Walk the Line : 'One of the Most Rewarding Experiences'

courtesy everette collection Reese Witherspoon in Walk the Line

Reese Witherspoon is reflecting back on her hit film, Walk the Line.

The actress, 44, celebrated the 15th anniversary of the biopic's release on Instagram Wednesday, sharing a photo of herself and costar Joaquin Phoenix dressed as their characters, country legends June Carter Cash and Johnny Cash.

"Wow! Today marks 15 years since the release of #WalktheLine 🎶," Witherspoon captioned the shot. "Playing the role of June Carter was one of the most rewarding experiences of my lifetime. From the stunning costumes created by @ariannephillips to recording all of those classic country songs with T. Bone Burnett, to the incredible scenes written and directed by James Mangold, I felt completely transformed into an authentic country artist 🌟."

Witherspoon, who won an Oscar for her role in the 2005 flick, went on to share one of her most memorable moments from its production.

courtesy everette collection Joaquin Phoenix and Reese Witherspoon in Walk the Line

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"I will never forget the proposal scene... how Joaquin looked with the light beaming behind him asking June to marry him in front of a full audience. You could hear a pin drop," she recalled.

The star ended her note by sharing her appreciation for those who worked on the film, writing, "Thank you to the entire cast and crew for bringing Johnny & June's love story to life.🎙."

Earlier this year, Witherspoon opened up about the vocal and music training she underwent in order to play the role of Carter Cash.

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"What a memory! Preparing to play June Carter was six months of singing lessons and autoharp training," she wrote in an Instagram post on May 14, sharing musical clip from the movie.

"Joaquin and the guys in the band practiced everyday and every night. Despite all the practice, I was so nervous to sing in front of those huge crowds, but once we got started it was such a thrill," she continued. "Truly an unforgettable experience I will always cherish."

In January, Witherspoon and Phoenix, 46, enjoyed a Walk the Line reunion when they both attended 2020 Golden Globes. The pair greeted each other on the red carpet with smiles and held hands as they chatted while Phoenix's fiancée, actress Rooney Mara, looked on.