Kesha has postponed a string of international tour dates as she undergoes surgery.

The pop star, 30, revealed that she had tore her anterior cruciate ligament in a message on Twitter on Tuesday, and would need to push back some of her performances.

She is scheduled to be performing in Australia throughout March before dates in New Zealand, Taiwan, and Japan in April.

“I’m heartbroken to be forced to postpone some of my upcoming international dates due to a recent injury I sustained while performing,” she wrote on Twitter.

“It’s my biggest joy in life to share my music with my fans all over the world, but I have to follow my doctor’s orders and undergo surgery today to repair my torn ACL so I can get ready to give it my all on my summer tour and beyond,” she added.

She is due to be touring throughout the US in June, July and August with rapper Macklemore.

Kesha returned with latest album Rainbow last year after suing her former producer Dr Luke in 2014 and accused him of of drugging, sexually abusing and emotionally tormenting her.

He vehemently denied the allegations and countersued.