A 19-year-old man going by the username GnashBrowns posted a despondent message on the web community Reddit, saying that he had been put off going to the gym by people laughing at him when he couldn't get his weightlifting form right.

Eventually, he said he gave up altogether: "Feeling completely embarrassed at this point, I put the bar and the weights in their places, and left with my head hanging low."

He was given support and advice on Reddit, but probably the last thing he was expecting was that Arnold Schwarzenegger might show up.

Schwarzenegger has used Reddit before, including for the popular AMA, or Ask Me Anything public forum question and answer sessions.

When another user on GnashBrowns' thread tagged him in to see if he could help, he joined in.

"I always say don't be afraid of failure, because how far can you really fall? You found out - to the ground. It's right there. Now you know it isn't anything that should scare you," he wrote in reply.

"You should be proud that you weren't afraid - not embarrassed that you failed," he wrote.

"You could have made excuses not to walk into the door, but you didn't. You knew it would be hard, and it would be uncomfortable, and it might be awkward - and you did it anyway. That's courage."

He added: "The last guy I rooted for broke a world record in the deadlift. You have more in common with him than you think."

A grateful GnashBrowns later posted that he couldn't wait to go to the gym again and would check in to Reddit's weightlifting community regularly to update them on his progress.

"This is my rest day so it's absolutely killing me not being able to go. But first thing tomorrow morning though, the tiny weights that I can pick up won't know what lifted them."

The Telegraph, London