Zac Efron is getting ''better every day'' as he recovers from his anterior cruciate ligament (ACL) tear.

The 31-year-old star revealed last month he had undergone surgery to repair his torn ligament - which is one of a pair of cruciate ligaments in the knee - after an extreme sports accident, but and now weeks later he has updated fans on his health as he continues to work hard to get back into shape.

Sharing a snap on social media of part of his training regime, Zac can be seen smiling as he raises one leg.

He captioned the photo on Twitter: ''Better every day. Taking it literally. 1 step at a time... thx for support everyone (sic)''

In February, Zac revealed he had suffered the injury whilst ''shredding the gnar'', a term used when someone excels in extreme sports such as snowboarding, skateboarding, surfing, or skiing.

He wrote: ''I tore my ACL shredding the gnar but all is good. I opted for surgery so I can come back stronger than ever. Thank you to Dr. Kvitne and his team at Kerlan-Jobe Surgery Center. I'll keep you updated as I heal and progress! Thanks for all the love and positivity! (sic)''

The actor - who will next be seen on screens as Ted Bundy in 'Extremely Wicked, Shockingly Evil, and Vile' - is known for his love of the outdoors, and once came face to face with a grizzly bear whilst on a hiking trip in Montana with his brother Dylan.

He said: ''Out of nowhere, [we were like] 'Okay, that's a bear. Everybody stop. And we all stood still. Somebody silently whispered 'But it's charging at us.' It took like two big canters at us.

''[Luckily it] disappeared behind some trees. It was the scariest part of the trip! But it was cool to see a bear that close. It was maybe 15 or 20 feet away. It was charging at us!''