Pop star Lily Allen, who will turn 30 in May, has changed her hair colour into pink and neon green.

Allen showed off her "watermelon" hair in latest Instagram photograph, reports aceshowbiz.com.

She captioned it: "Not long till I'm 30, one last hurrah on the hair front. Watermelon hurr dun care."

After sharing the photograph, Allen was spotted out and about in West Hollywood.

Allen is no stranger to hair colours. She previously rocked light blonde as well as lavender-silver ombre.