Taylor Swift on Tuesday by sharing four of her “favorite songs” with the crowd in Zurich, Switzerland. The pop icon, 34, told the audience the show marked a special milestone because it included the number 13, which she famously and that’s my favorite number, which I never mention,” she joked with the audience, in a quote obtained by People Magazine. “I just thought since it was my favorite number, I’d do some of my favorite songs for the acoustic section.

” Swift then surprised fans with a mashup of “Right Where You Left Me” from her album “evermore” and “All You Had to Do Was Stay” from “1989.” She followed it up with a piano mashup of telling the audience “Happy July 9th to those who celebrate.” The “Bad Blood” singer was apparently referencing another milestone — the one-year anniversary of the release of “Speak Now (Taylor’s Version),” the re-recorded version of her 2010 album.

The date, July 9, is notable in Swift’s discography as referenced in “Last Kiss,” in which she sings, “That July 9th / the beat of your heart / It jumps through your shirt / I can still feel your arms.” Tuesday’s show was also significant in that it marked during her 18-year career. During her previous tour stop in Amsterdam, she was joined by boyfriend and Super Bowl champ Travis Kelce, who during one acoustic song mashup that included a nod to his 87 jersey number.

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