Pop singer Lorde has apologized for a flippant remark in a recent interview, which some took as being insensitive to her close friend Taylor Swift.

In a weekend interview with the U.K. newspaper The Guardian, Lorde, 20, was speaking of the difficulty of friendships with particularly high-profile celebrities such as superstar singer Swift. “It’s like having a friend with very specific allergies,” Lorde, born Ella Yelich-O’Connor, said. “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. It’s like having a friend with an autoimmune disease.”

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Media outlets picked up on the remark, and one Twitter commenter, Stephanie Marie, an editor with the Australian diverse-sexuality website SBS Sexuality, wrote on Monday, “I wonder how @selenagomez [who has been diagnosed with lupus] feels about this. What an incredibly ignorant analogy to make @lorde.”

Lorde replied, “Didn’t mention taylor, but regardless, i [expletive] up & that was really insensitive. i’m sorry.” She ended with an emoji of a red rose.

Lorde and Swift, 27, have been close friends for years. In September 2014, Swift told Rolling Stone that her friendship with Lorde, whom she calls Ella, was “like this blazing bonfire,” adding, “You can either be afraid of it because it’s so powerful and strong, or you can go stand near it, because it’s fun and it makes you brighter.”

Lorde was one of several guest singers in Swift’s 1989 World Tour, performing with Swift at Nationals Park in Washington, D.C., on July 13, 2015.

“Bad Liar” singer Gomez, 24 has not responded on social media.