Kell Brook faces the toughest test of his illustrious boxing career this weekend.In the early hours of Sunday morning UK time, the Sheffield-born fighter will step into the MGM Grand's ring to take-on the imperious Terence 'Bud' Crawford.The American WBO welterweight champion is one of the finest athletes in the business and is currently ranked as the sixth best pound-for-pound fighter in the world on Boxrec.Last April, Crawford destroyed Brook's English rival Amir Khan in Madison Square Garden and it's feared he'll do the exact same to Special K.However, Brook will have a significant weight advantage going into the fight as there is no rehydration clause.Brook at the weigh-inAt the weigh-in yesterday, the Englishman - who displayed a seriously ripped physique - played on that fact, telling Crawford during a socially-distanced face-off, per Sky Sports: "I look like a beast now!"To be fair to Brook, he looks incredible, but so does Crawford - as you can see in the photos below...

But physiques don't always win fights and Crawford fired back at his upcoming opponent: "Cool. 170[lbs], 180[lbs], 200 [lbs], it don't matter. I'm going to fill up too."

The fact Brook will be the heavier of the pair come fight night certainly adds a new layer of intrigue to the bout.

Nevertheless, Crawford has the ability to brush aside that 'advantage' with ease.

The Nebraska-born fighter was an undisputed champion at super-lightweight and has not lost a single one of his 36 professional bouts, winning 27 by way of knockout.

Brook on the other hand has struggled in the recent years of his career, losing to Gennady Golovkin and Errol Spence Jr. in the space eight months.

Since his loss to Spence Jr. in May 2017, Brook has had just three fights and while the 34-year-old has won them all, they've been against low-level opponents.

Stepping into the four-cornered ring against one of the greatest fighters of the modern era will likely be too much of a step up, but in boxing, you just never know...