A hacker has targeted US pop star Miley Cyrus in a YouTube attack, wrongly telling fans the teenage singer had died.

Using the "mileymandy" YouTube account, which features Cyrus and her friend Mandy Jiroux, the hacker posted a video that appeared to be from Jiroux.

"We're very hurt to tell everyone this, but Miley died this morning after being hit by a drunk driver," text in the video read.

"She always told us if anything ever happened to her, then tell her loyal fans first before the public ... RIP Miley, we will miss you so much."

Cyrus is the daughter of country music singer Billy Ray Cyrus and stars as Miley Stewart/Hannah Montana in the Disney television series Hannah Montana.