Singer Noah Cyrus has apologised after using an "offensive" term while defending Harry Styles.
Styles was criticised by prominent US conservative commentator Candace Owens after posing in a Gucci ballgown on the cover of Vogue.
Owens, who is black, tweeted: "Bring back manly men."
Pop star Cyrus, 20, shared a picture of Styles in the dress on her Instagram Story and said he wears it "better than any of u nappy ass heauxz".
Nappy is sometimes used to describe afro-textured hair and is widely seen as offensive to black people.
Cyrus, the younger sister of Miley, apologised and said: "I am mortified that I used a term without knowing the context and history, but I know now and I am horrified and truly sorry. I will never use it again. Thank you for educating me.
"I in no way meant to offend anyone. I am so so sorry."
Styles had already responded to the controversy over his dress.
He posted a picture to Instagram, posing in a powder blue suit with a cinched and ruffled waist while holding a banana in his mouth.
The singer captioned the post: "Bring back manly men".