John Cena starting working out for a truly heartbreaking reason

John Cena is one of the all-time WWE greats. And part of his success, which has seen him gain millions of fans, is down to the fact he is absolutely jacked.

However, as he revealed a few years back, there is actually a dark story to why he began hitting the weights in the gym.

Like a lot of people, the Hollywood star was bullied as a kid, and was 'beat up a lot' when he was younger.

So, in a bid to boost his confidence and warn off any bullies that even thought about stepping up to him, he started working out. Like, really working out.

Speaking about his younger years, Cena told Howard Stern: "I started working out when I was 12 years old.

"It was a true comic book story. I was getting beat up every day in junior high, I finally started working out... "

When asked if he did any self defense to go with it, the 45-year-old said: "Not even, just that [size] is a pretty intimidating thing."

The Howard Stern Show

This isn't the first time Cena has opened up about his childhood, though.

A few years ago, he became the brand ambassador for Crocs' 'Come As You Are' campaign.

In an ad for the campaign, he said: "I remember the walk to the school bus. At the very least, five times shoved down, toppled down.

"I asked my dad, 'Is it ok if I start working out?'

"By the time I was showing up at high school, I was big. The guys who were pushing me down were kind of like, 'We cool?'

"Never once did I ever get back at any of those guys.

"As horrible as a time that it was for me, it was a catalyst for me to find a passion of my life. Everybody goes through those moments of self-doubt and whether they're a moment or whether they're a wall that you can't climb over, 'Come As You Are' means be authentic.

The Howard Stern Show

"Means don't be afraid to be who you are. I'm very emotional, as cold as I seem sometimes, I'm a sucker, I'm like stupid in love and if that doesn't make me cool then whatever - I don't want to be cool."

Talking to the Huffington Post, Cena, who was the second oldest of five brothers, said he always found it hard to make friends.

He said: "I really never socially matched that well with kids as an adolescent or early teenager. Never once did I waver or try to conform like a group philosophy. I was always pretty much an oddball.

"I haven't really run into a lot of folks that say that they weren't bullied as a kid. Nowadays, especially with social media, there is a lot of bullying going on."