Niall Horan celebrates knee progress

One Direction singer Niall Horan is celebrating after making more progress with his left knee following surgery last year (14).

The pop star underwent an operation on the joint to correct a long-running problem in January, 2014 and was still recovering from the surgery when One Direction began a world tour in April (14).

Horan has now revealed he has only just been able to fully bend the knee 18 months on by sharing a close-up picture of his foot touching his bottom in a post on Instagram.com.

He writes, "First time I've been able to touch my a**e with my heel since I got the operation. Sounds so dumb, but it's a big day in my head haahah (sic)!"