The pop star is preparing to release her sixth studio album on 10 November, and apparently "stalked" fans to hear the record in its entirety ahead of time.
As well as getting a sneak peak of the new music, fans who were hand-picked for the secret sessions got to meet her on Friday 13 October, and also went away with a few treats.
Photos posted on Instagram and Twitter accounts showed fans revealing snake-shaped key chains and a few scarce details about what happened.
Secret sessions were introduced for Swift's new releases just before her last album 1989 was released in 2014.
At the time she held special events at her homes in London, Nashville, New York City, Los Angeles and Westerly, R.I.
Here are some posts from fans who attended:
Fans also reported receiving chicken nuggets, M&Ms, and Reputation themed cookies through the night. They wrote that Swift was the "happiest she has ever been".
She recently achieved her first ever UK No.1 single with "Look What You Made Me Do". Her new album Reputation is out on 10 November via Big Machine Records.
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