Taylor Swift has addressed her songwriting pseudonym in a new artist-on-artist interview with Paul McCartney.

The pop star, who this week chatted to The Beatles legend for Rolling Stone, said “nobody knew for a while” about her co-write on Calvin Harris‘ (feat. Rihanna) 2016 song ‘This Is What You Came For’. She disguised herself under the name Nils Sjöberg.

“I wrote under the name Nils Sjöberg because those are two of the most popular names of Swedish males,” Swift told McCartney. “I wrote this song called ‘This Is What You Came For’ that Rihanna ended up singing. And nobody knew for a while. I remembered always hearing that when Prince wrote ‘Manic Monday’, they didn’t reveal it for a couple of months.”

McCartney added to the discussion: “Yeah, it also proves you can do something without the fame tag. I did something for Peter and Gordon; my girlfriend’s brother and his mate were in a band called Peter and Gordon. And I used to write under the name Bernard Webb.”

Swift’s co-write on Harris’ single was revealed a few months after its release in April 2016. She reportedly first used the pseudonym, Nils Sjöberg, for that song in order to keep the attention on the music and not on her relationship with Harris, whom she dated for 15 months between 2015 and 2016.

Elsewhere in the interview, McCartney revealed that he wanted to invite Swift on stage with him at Glastonbury 2020 to play ‘Shake It Off’ together.

The pair were set to headline the Pyramid Stage at this year’s festival before it was called off due to the coronavirus pandemic.

The duo also talked about their two quarantine albums. In July, Swift surprise-released new album ‘Folklore’, which she made largely with The National‘s Aaron Dessner during lockdown.

McCartney, meanwhile, recently announced new solo album ‘McCartney III’, ending the 40-year wait for the completion of his trilogy of self-titled albums.