Tears begin to well in Dwayne “The Rock” Johnson’s eyes and his voice wavers as he talks about the day he unwittingly gave a boost to an Australian boy’s life.

It was a simple act on the Hollywood action hero’s behalf.

Johnson has never met the boy, but has only heard his story.

It all happened two years ago when the massively built Johnson was shopping at a toy store at The Grove, an upmarket Los Angeles outdoor shopping mall for a present for his daughter, Simone.

An Australian tourist recognised him, nervously tapped him on the shoulder, pulled out a scrap piece of paper she had in her handbag and asked for his autograph.

Johnson smiled and happily signed the autograph, thinking it was for the woman.

The meeting only took a couple of seconds and the woman, not wanting to bother him any further, said thank you and left him to finish his shopping.

Being mobbed by autograph hunters happens to Johnson whenever he goes out in public and he is happy to sign them.

This one had a different outcome.

Johnson only heard about how the autograph helped the boy a few weeks ago when another Australian he met relayed the story.

Apparently the tourist was a social worker who knew the piece of paper would help a troubled boy by giving him hope.

The child had a hellish upbringing – living in an abusive home – and was on his way to growing into a troubled adult.

His one passion in life was professional wrestling and he was a huge fan of Johnson.

“… The kid was in a bad place. But the autograph changed his life around.”

“That’s cool,” the actor said, grinning.

Johnson brought up the story while promoting his new $US60 million action film, Doom, which opened number one at the US box office last weekend and hits Australian theatres on Thursday.

It confirms his belief celebrities should never complain about fame, especially signing an autograph or posing for a photo.

When he hears other actors whining about it, the clean cut 194cm, 135kg former college American football player feels like bodyslamming them.

“How hard is it to do an autograph?” Johnson, who has starred in action films The Mummy Returns, The Scorpion King, Walking Tall and the comedy, Be Cool, asks.

“It annoys me when actors say ‘Don’t take my picture, I just want to be left alone’.

“Well, then stop going out if you want to be left alone. Stop going to that restaurant.

“Stop going to The Ivy.

“Shut up!”

When you become a successful actor, he says, you have to live with the consequences.

It is especially hard for Johnson, who towers over most people in public.

“Your anonymity goes out the window,” the 33-year-old said.

“I’m not one of the actors who can just kind of hide because I’m not a small guy.

“It’s not negotiable for me.

“I make movies. It is what it is.

“Who is complaining? Why are they complaining?”

Doom is the long-awaited film based on the landmark video game of the same name which revolutionised the video game industry when it was released in 1993.

Set in the future, it follows a squad of marines called in to investigate a scientific facility on Mars that has been overrun by nightmarish creatures.

Often Johnson plays likable characters, but in Doom he is Sarge, the leader of the marines who has a dark side and butts heads with offsider, New Zealand actor Karl Urban, who fills the role of good guy, John “Reaper” Grimm.

Universal Pictures initially offered Johnson the role of Grimm.

“I have to play with what intrigues me,” Johnson says.

“First they sent me the script for Reaper. I read it and then called Universal and said ‘There’s an anti-hero, Sarge, who I like who has a few layers to him and has to make tough decisions’.

“The hero always wants to save the world.

“Will Smith, who is a buddy of mine, always saves the world, but this time I thought it would be more interesting for me to try and end the world.”

There was also another bonus to the role.

“Selfishly, Sarge gets to carry the BFG,” Johnson laughed.

The BFG, which stands for Big F…… Gun, is a weapon in the Doom video game.

“I’ve always been a big fan of Clint Eastwood,” Johnson explained.

“He’s my favourite. He had his Magnum and Arnold had his big gun in the Terminator.

“I said to (Doom director) Andrzej Bartkowiak ‘If we have the BFG I can literally have the biggest gun in the history of movies and he was like ‘Yeah, baby let’s have it’.”

The film was shot in Prague, in the Czech Republic, and that meant Johnson was away from his wife Dany and four-year-old daughter for months.

That was tough.

The reality the director and producers created on the Doom set was also unsettling.

“By far for me, it was the most gruelling, mentally taxing movie I have made,” he said.

“…It was very intense because every day there was someone dying and all of the bodies on the floor weren’t dummies.

“They were amputees – real people.

“Between make-up and prosthetics, it looked like literally their arms and legs were yanked off.”

credit: seven.com