Demi Lovato has injured her arm.

Alongside the snap, she wrote: "Welp. Looks like I won't be playing guitar, piano OR drums tonight. San Antonio... Why did you have to go and make me fall so hard for you?!! #demiworldtour (sic)."

This isn't the only injury the brunette beauty has sustained this summer as she also sprained her ankle in July after going for a quick run.

She tweeted, alongside a picture of her swollen ankle, at the time:

"Umm soooo... I guess when I went running and twisted my ankle I actually did hurt myself... AGAIN. Hahaha (sic)."

Meanwhile, Demi, who sought treatment in rehab for eating disorders, drug abuse and a self-harming disorder in late 2010, has hired activist Spencer West to share "his empowering message" before she takes to the stage every night in favour of a warm-up act.

Announcing the news on her Facebook page yesterday, she said: "Spencer West is not only a really great friend of mine, but a huge inspirational speaker. After I spent some time around him and realised what an amazing person he is and how incredible he is at speaking, I decided to bring him on tour."