EXCLUSIVE: Andrew Johns opens up on retirement battles - 'I had some dark times'

Rugby league legend Andrew Johns has opened up about the struggles he faced when he realised his sporting career had ended.

Johns is arguably the best footballer to ever strap on a boot. He won three Dally M Medals and two premierships with the Knights during what was one of the most decorated careers ever.

He played two games of the 2007 season before realising his time had come, and his body wouldn't allow him to continue playing professionally.

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"I knew I was done," Johns opened up in a candid interview on Wide World of Sports' Immortal Behaviour.

"In the off-season there were some moments. My body kept breaking down, I kept doing my hamstring. It was just a sign my body was breaking down. In a way it did me a favour, because I knew I was shot, I knew I was gone.

"I didn't want to embarrass myself, and I didn't want to embarrass the jersey, going too long.

"I just knew it was time. Whether it was meant to be or not... I think it was round two or three I ended up finishing up.

"In the end it was like a relief. But geez it was hard, the transition."

Johns began working with Channel Nine, but he found it hard to adjust to life with the routine of a professional athlete.

He revealed he "ended up breaking down" when a friend approached him at the beach one day, and asked if he was "lost".

"I was lost for 18 months. I had some dark times," Johns said.

"When you think about it I went from school, pretty much straight into professional footy. So from 18 to 32, everything... on Monday I'd be given a sheet of what I had to do (for the week), what I had to wear, follow a pretty strict diet.

"Then all of a sudden you retire and there's none of those rules, there's none of that routine. And you have this competitive monster inside you.

"You know it's coming to an end, but in your head you're still in that bubble, and then all of a sudden it's all gone.

"I reckon it took 18 months to get my head around it. It's hard to describe. The routine, the discipline, the rules, where you had to be. Every day you're competing against yourself and your teammates. Then all of a sudden it's a totally different world."

Johns now makes sure to lend an ear or a shoulder to any athlete struggling with the thought of retirement.

"It's something that I'm always conscious of when players I know retire, I check in on them," he said.

"Some really struggle. There's things in place now, and clubs have welfare... but it's a real issue."