Singer Demi Lovato marked her second clean and sober anniversary with four new piercings in her ear at the weekend (15Mar14).

In 2010, the Heart Attack hitmaker entered a rehab facility in a bid to seek treatment for a series of personal issues, and, after a lengthy stay, she emerged sober and eager to enter the next phase of her career.

On Saturday, the 21 year old took to Twitter.com to share her sobriety milestone with followers, and wrote, "Today is my 2nd birthday. I'm 21 years old, but 2 years ago today, I finally started living... I'm so beyond grateful."

To celebrate, she posted a close-up shot of her left ear, clad with two diamond studs and two small gold hoop rings, along with a caption which read: "Why not celebrate with some new piercings? 4 in one sitting."

Lovato, who also stunned fans earlier this month (Mar14) by sporting a partly shaved head, is currently in the middle of her Neon Lights world tour.