5 things you didn't know about WWE Superstar John Cena

When John Cena debuted on WWE SmackDown in 2002, few could've expected the monumental success he would have.

Losing in his debut match to Kurt Angle, Cena personified 'Ruthless Aggression', refusing to give up despite this setback.

At WrestleMania 20, Cena got his first taste of championship gold, winning the US Title from the Big Show, and established himself as the man a year later, defeating John 'Bradshaw' Layfield to win his first of 16 World Championships.

Since that fateful April night in 2005, Big Match John has gone on to become a huge star in and out of the ring, recently transitioning to a growing career in Hollywood, where he will next star in the upcoming Transformers prequel, Bumblebee.

But despite his massive success, there are still a lot of things fans may not know about him.

Here are five things you (probably) didn't know about John Cena.

#5 His brains match his brawn

Cena returns as the Doctor of Thuganomics in 2012.

If you ask any WWE Superstar what you should do before joining the company, most will tell you to get some sort of qualifications outside of the ring.

After all, in just an instance a career can end, leaving a suddenly-retired Superstar trying to find other ways to get by.

Cena, is no exception to this, as the Cenation leader earned a degree in Exercise Physiology from Springfield College in Massachusetts.

Speaking to Men's Fitness, Cena said how his knowledge of the human body and exercise has helped him learn more about how to improve his body, as well as knowing when something is being strained.

Clearly, this degree in Excercise Physiology has paid off, as the 41-year-old is still in excellent condition all these years later.

#4 He is a huge K-Pop fan

Throughout his WWE career, Cena has been at times, a symbol of the American spirit.

Whether battling foreign heels such as Rusev, or proudly wearing the US Title on five separate occasions, Cena has been a true symbol of Americana.

Which is why it has surprised many fans to discover Cena is a huge fan of Korean Pop music, in particular, the extremely popular BTS group.

Speaking to the UK's METRO newspaper, Cena confirmed his devotion to the group, though was coy on explaining how he got into them.

See, if I were to explain, that would defeat the purpose! Although I will say, 'Base Line' is my favorite track on the j-hope mixtape. I also like 'Hangsang'."

"What started as a happy accident has turned into something wonderful. I've been introduced to a new piece of culture, which I think is fantastic because I'm learning through social media."

#3 His first championship wasn't in WWE

Cena preparing to compete as the Prototype.

For years, John Cena would tell the fans 'the Champ, is here!' and with good reason.

Across his WWE career, Cena has held 16 world championships (a record only tied by Ric Flair), as well as multiple United States and Tag Team Championships.

But despite all his accolades in the WWE, Cena's first title came before he'd even signed with Vince McMahon.

Appearing as 'The Prototype', Cena competed for Ultimate Pro Wrestling, winning the UPW Heavyweight Championship in April 2000, from the unfortunately-named 'Smelly'.

After a 27-day reign, Cena would lose the title to Smelly though continued working with the company until March 2001.

Interestingly, UPW helped give a lot of wrestlers their big breaks, as Samoa Joe, The Miz and Christopher Daniels all competed for the company at some point, before it closed in 2007.

#2 He was very nearly let go

At this point in his career, John Cena is practically untouchable in WWE, and it would take a lot for the company to cut ties with him.

But not long into his WWE debut, the company were considering just that, as Cena was failing to impress.

With his simple trunks and methodical pace, Cena was seen as extremely bland by those backstage and was very nearly let go because of it.

Fortunately, Stephanie McMahon caught Cena backstage, demonstrating his freestyle rap skills, and took a liking to the young Superstar.

Within weeks, Cena was re-introduced, now as a trashy rapper, who was spitting rhymes on his opponents before matches.

The gimmick quickly got over, and Cena became a huge star from it. Saving his career, Cena remained on SmackDown, before moving to RAW in 2005, and the rest is history...

#1 He holds the record for Make-A-Wish

Cena has helped over 500 children's dreams come true.

Cena has his fair share of critics, but even they cannot deny the man's giving personality and warm heart.

When not entertaining his fans on screen, Cena still gives and has worked closely with the Make-A-Wish foundation, making dreams come true for children in the most horrific of circumstances.

In fact, Cena holds the record for the most wishes granted by a single person, having granted over 500 wishes with the organization.

Speaking to ESPN on why the charity means so much to him, Cena talked about how moving the process is, for both the recipient as well as him.