Mixxyville

Fans attending Sam Smith’s “To Be Free: San Francisco” residency at the iconic Castro Theatre were treated to an unexpected and unforgettable moment when rising singer Sienna Spiro joined the stage as a surprise guest.

The performance took place during Smith’s intimate residency shows celebrating the long-awaited reopening of the Castro Theatre, a designated landmark located in the heart of San Francisco’s LGBTQ+ cultural district. The venue recently reopened after undergoing two years of renovations, making the residency even more meaningful for fans and the city.

During the show, Smith invited Spiro onstage for a powerful duet of her breakout single “Die On This Hill.” The emotional performance showcased both artists’ stunning vocals and instantly became one of the standout moments of the night.

The duet also marked a full-circle moment for the pair. Spiro previously opened for Smith during the “To Be Free: New York City” residency in late 2025, where the two performed a memorable duet of Smith’s hit song “Lay Me Down.”

At just 20 years old, Sienna Spiro is already gaining global attention for her powerful voice and emotionally driven songwriting. Her breakout single “Die On This Hill” has quickly become a major success, reaching the Top 10 on Spotify’s global chart and landing inside the Top 20 of the Billboard Hot 100.

The rising artist recently launched her first North American headlining run, The Visitor Tour, which sold out within seconds due to overwhelming demand. The tour kicked off at the historic Troubadour in Hollywood to rave reviews, with critics praising Spiro’s vocal performance and stage presence.

She will continue the tour across the United States before wrapping up with two shows at New York’s Bowery Ballroom on March 17 and 18. Spiro is also set to release her new single “The Visitor” on March 13 via Capitol Records.

Meanwhile, Sam Smith’s “To Be Free” residency series continues to bring fans closer to the artist in intimate settings. The performances feature some of Smith’s biggest hits along with previews of new music, including the recent single “To Be Free,” which explores themes of vulnerability, freedom, and emotional honesty.

With surprise collaborations like the duet with Sienna Spiro, the residency continues to deliver special moments for fans lucky enough to experience the show live.