Rocky Fielding is writing his own Rocky story after a remarkable turnaround in his career this year, which he hopes to continue this weekend.

Fielding is not even the most famous boxer in his home city of Liverpool, but on Saturday he faces arguably the most famous boxer in the world.

Fielding (27-1, 15 KOs) defends his WBA "regular" super middleweight title, a less prestigious version of the world title, against Canelo Alvarez at Madison Square Garden, New York, in a fight nobody predicted or had called for.

Callum Smith, Fielding's fellow Liverpool boxer who knocked him out inside a round three years ago, holds the full WBA world title, and yet it was Fielding who got the call.

Alvarez (50-1-2, 34 KOs), along with heavyweight Anthony Joshua and lightweight Vasiliy Lomachenko, is one of boxing's biggest stars and recently signed a guaranteed $365 million television contract with sports streaming service DAZN.

Fielding, in contrast, has spent most of his career in the shadows earning a fraction of what Alvarez is used to.

At the start of this year, Fielding even feared for his career despite compiling a series of wins since his humbling experience against Smith.

"From the start of the year to the end of the year has been crazy," Fielding said to reporters the day before he traveled to the U.S.

"At the start of the year I didn't know where I was going, I was having no dates. Then I had five weeks' notice to fight Tyron Zeuge.

"I was training for six months not knowing what was going on, then I won the title. I heard James DeGale and Chris Eubank's name being mentioned and when my trainer Jamie Moore rang me I thought he wanted me to spar one of them. Instead he said Alvarez wanted to fight me."

Fielding has defied the odds more than just the win over Zeuge for the WBA belt in Germany via fifth round stoppage in July. The 31-year-old got his first opportunity to make a name for himself on live television in the UK after only four professional fights.

And Fielding capitalized on it to win the eight-man competition Prizefighter, after triumphing in three three-round fights on the same night in March 2011.

Even after winning Prizefighter, after entering the tournament as a late replacement with less than a week's notice, Fielding made steady rather than promising progress.

Landing the Alvarez fight has been the biggest thing -- by far -- that has happened to Fielding as a boxer. But 12 weeks ago, partner Jess gave birth to their second child, Romi.

Rather than go away for training camp, as a lot of boxers do, Fielding has enjoyed being based at home, where he has split preparing for Alvarez and his dad duties for Romi and 2-year-old Ralphi.

"This is better than being away for training," Fielding said.

England's Rocky Fielding, left, won his "regular" super middleweight belt by defeating Germany's Tyron Zeuge in July. Uli Deck/dpa via AP

"I did go to Tenerife a few months back and it killed my routine. Now I get home and it's bedtime, it's bath time, and I won't have seen the children since the morning.

"It makes me bounce out of boxing, I put all my spare time into being a dad. Once I walk into the gym I'm all about boxing, but when I'm home, it's about being a dad.

"Don't get me wrong, I still think about boxing but I have to mix in at home as well and I enjoy it. My daughter is 12 weeks old and I've been in a training camp for 10 weeks. So I haven't held her properly and been out pushing the pram, doing the little things. But when I'm slugging it out and things are getting tough I just think, 'everything is for the kids.'

"Every punch I throw now is for their future. When it's going tough in a session I have a little think about why I'm doing it, what I'm getting up for and why I'm putting myself through it."

Fielding, a lanky 6-foot-1 fighter who hits hard to the body, has trained alongside middleweight world title challenger Martin Murray since early in his professional career.

Trained by Moore in Manchester, Fielding also prepares for fights alongside former world featherweight and junior featherweight Carl Frampton, due to challenge Josh Warrington for the IBF featherweight title on Dec. 22.

"You push yourself when he's [Frampton] there, on the runs, when you're sparring, he's a good, good person to be around and an experienced fighter," Fielding said.

"The whole gym is like that, Martin Murray, Tommy Coyle. Training alongside Carl has been great He's a former two-weight world champion; he's done it all."

Alvarez, who has beaten four Britons (Matthew Hatton, Ryan Rhodes, Amir Khan and Liam Smith), opted to face Fielding after outpointing Gennady Golovkin to become the world middleweight champion in September.

Alvarez, of Mexico, is in form but Fielding hopes size and his height advantage will help him pull off a huge upset.

"Weight is key," Fielding said. "He's had most fights at junior middleweight and when he has stepped up to middleweight, he has been the biggest, but he's nowhere near the biggest at super middleweight.

"But I've had a good camp and it's on the night what happens. I've been up against it in my last fights and have done the business. I'm going in there to win and I'm confident.

"He has been a monster at junior middleweight and stepped up and beaten GGG, Julio Cesar Chavez Jr. on points, Miguel Cotto.

"So I'm in there in good company. If you want to be the best you have to fight the best. It's on the night what happens."