Sam Smith surprised fans during their 20-date “To Be Free: San Francisco” residency at the Castro Theatre with an appearance from Sienna Spiro. The two artists performed a duet version of Spiro’s breakout hit “Die On This Hill” at the recently re-opened landmark venue in the heart of the city’s LGTBQ+ cultural epicenter.

“I LOVE San Francisco and The Castro especially has been so central to the Queer community here over the years,” said Smith in a statement regarding the residency. “These shows will also celebrate the official reopening, so it’s truly an honour to become part of this iconic venue’s history.”

Spiro was recently the opening act during Smith’s “To Be Free: New York City” residency, which took place in late 2025 at Brooklyn’s historic Warsaw club. The pair delighted fans with a duet of Smith’s “Lay Me Down,” which appeared on their 2014 debut studio album In the Lonely Hour.

The residency takes its name from Smith’s single “To Be Free,” which features the TwoCity Chorus, a collective of recording artists from Philadelphia and New York City curated by Brandon Pain and Ant Clemons.

The 20-year-old Spiro recently embarked on “The Visitor Tour,” her first-ever North American headlining run. After selling out within seconds, additional dates were added. The U.S. dates of the tour wrap up later this month with back-to-back nights at New York’s Bowery Ballroom. On March 13, Spiro will release her new single “The Visitor” via Capitol Records.

“Die On This Hill” gave the British singer-songwriter her first Billboard Hot 100 entry. Spiro, who first built her audience on TikTok, has been enjoying breakout success in recent years thanks to the success of singles like “Maybe,” “You Stole The Show,” and now “Die On This Hill.” She was nominated for the Critics’ Choice Award at this year’s BRIT Awards.

Buy Sienna Spiro’s Die On This Hill on vinyl here.