“The lyrics to ‘Shake It Off’ were written entirely by me,” Swift said in her declaration filed 8 August.
This is the second time that Swift has had to defend the lyrics for the song.
The copyright lawsuit was originally filed in 2017, but later dropped.
However, after it was appealed one year later, a judge recently ruled that the case would go to trial and be decided by a jury.
The claim was filed by songwriters Sean Hall and Nathan Butler, who are accusing Swift of plagiarising their 2001 track “Playas Gon’ Play’’ for band 3WL.
However, Swift says that she didn’t even know the song existed: “The first time I ever heard the song was after this claim was made.”
In the declaration, Swift strongly denies that she stole any lyrical content, using childhood stories to evidence her point.
“I recall hearing phrases about players play and haters hate stated together by other children while attending school in Wyomissing Hills, and in high school in Hendersonville,” Swift said.
She argued that these popular phrases had inspired lyrics for the song, pointing out that it was unrealistic for people to claim sayings that are omnipresent in society.
“I also recall hearing similar player and hater phrases in many songs, films and other works prior to ‘Shake it Off,’” she said.
The musician also detailed how 2014’s “Shake It Off” came about with co-writers Max Martin and Shellback.
Swift claims that Shellback made the drumbeat, while Martin and Swift collaborated to make the melody. Swift then ad-libbed the lyrics, she claims.
Co-writers Martin and Shellback also deny hearing the song prior to the lawsuit.
“Shake It Off” appears on Swift’s fifth studio album 1989.
Meanwhile, Swift fans are divided over her private jet usage, after the star was revealed as having highest Co2 emissions out of any celebrity this year.