By Alexia Fernandez, People
June 20, 2017

This originally appeared on 

has come under fire after comparing her friend to an “autoimmune disease” in an interview with  on Saturday.

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 might () 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 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 of herself, Swift and model .

A bunch of stars turned out for the singer’s bash, including , , , Kloss, and .

Ahead of the party, Swift penned a sweet tribute to her friend which she .

“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 showing a water-painted birthday card for the Lorde (whose real name is Ella Yelich-O’Connor).