The Shake It Off hitmaker is in the middle of her 1989 World Tour, and she has already recruited stars including Julia Roberts, Matt LeBlanc and John Legend for cameos.

Her surprise guests have made headlines over the past few months, but Swift admits most of the appearances were agreed upon at the last minute.

In an interview with the Associated Press, Swift says, "Interviewers always ask me how we 'get' these people to come to the shows to walk, and the truth is that everyone who has walked the catwalk at one of the shows was already there just to see the show.

"Usually I ask them in my pre-show meet and greet if they want to come out on stage, then I'll explain to them how the stage/elevator lift works and we just wing it."

Speaking of the unlikely pairing of Roberts and folk singer Joan Baez at her gig in Santa Clara, Caifornia, Swift adds, "Joan Baez and Julia Roberts were both at my show in Santa Clara, and they were in my meet-and-greet room together. Julia is such a huge Joan fan and they were really hitting it off. I asked them if they wanted to walk out onstage together and Julia's kids exploded into 'Please!!' So that's how that happened."