Speaking on the difficulty of maintaining a close friendship with someone as famous as Swift, 27, Lorde told The Guardian, “It’s like having a friend with very specific allergies. There are certain places you can’t go together. Certain things you can’t do.”
“There are these different sets of considerations within the friendship,” Lorde continued. “It’s like having a friend with an autoimmune disease.”
After a fan mentioned how fellow Swift friend Selena Gomez might (who suffers from lupus) feel about the disease comment, Lorde apologized on Twitter, writing, “didn’t mention taylor, but regardless, i f—– up & that was really insensitive. i’m sorry.”
The two musicians are close friends, with Swift throwing Lorde a 20th star-studded birthday party in November.
“Had the best birthday party I’ve ever had tonight surrounded by my nyc family. all organised by tay who is as she says ‘a mom with no kids’. i am ur kid and u love me so hard i could burst. here’s to our 3 magic years of best friendship and more moments like this squished between angels,” the singer wrote in an Instagram photo of herself, Swift and model Karlie Kloss.
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Ahead of the party, Swift penned a sweet tribute to her friend which she posted on Instagram.
“Thank you for the music you make, the advice you give, the thoughts you provoke, and the way you’ve made my life more beautiful since the first day we met up in New York and ate burgers on a park bench and got attacked by squirrels. I. Love. You. So. Much. Ella,” Swift captioned an Instagram photo showing a water-painted birthday card for the Lorde (whose real name is Ella Yelich-O’Connor).
This article originally appeared on People.com