So far in 2017, boxing's had a serious of big fights: Anthony Joshua vs. Wladimir Klitschko for the heavyweight championship, Canelo Alvarez vs. Julio Cesar Chavez, Jr., Keith Thurman vs. Danny Garcia and Gennady Golovkin vs. Danny Jacobs.

The run continues on Saturday afternoon live on Showtime starting at 4:15 p.m. ET in a battle of the No. 2 and No. 3 147-pound fighters in the world. Kell Brook is defending the IBF welterweight title against Errol Spence Jr. from soccer stadium Bramall Lane in Sheffield, England, in where 30,000 people are expected to be in attendance.

"Brook versus Spence is a fight that pits two of the best, if not the best fighters in the welterweight division," executive vice president and general manager of Showtime Sports Stephen Espinoza told Sporting News. "We will look back and realize this welterweight division is one of the deepest in history and they are fighting each other."

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Brook (36-1, 25 KOs) captured the title from Shawn Porter in 2014. He's coming off the first loss of his career in September when he moved up two weight classes to middleweight and lost to unified champion Gennady Golovkin by fifth-round TKO. While Brook may have lost the fight, he gained respect from boxing fans around the world. He stood toe-to-toe with "GGG", won a couple rounds until the power adnd size advantage became too much for Brook.

The 31-year-old moves back down to his normal division to establish himself as the best welterweight in the world.

Spence Jr. (21-0, 18 KOs) was a member of 2012 Olympic team and is regarded by many including the best boxer of this generation Floyd Mayweather as the future of boxing. He hasn't fought since August when he notched a sixth-round knockout over Leonard Bundu.

This is the biggest test of Spence's young career. No one is sure if the 27-year-old is ready to jump into the lion's den but there's only way to found out.

Brook vs. Spence Jr. on paper should be a great fight between two great fighters.

Here is everything you need to know about Kell Brook vs. Errol Spence Jr.

All times are Eastern.

Kell Brook vs. Errol Spence Jr. start time

The Brook vs. Spence Jr. broadcast starts at 4:15 p.m. with Brook and Spence Jr. expected to enter the ring at around 4:45 p.m.

Kell Brook vs. Errol Spence Jr. channel

Kell Brook vs. Errol Spence Jr. can be seen on Showtime at 4:15 p.m..

Kell Brook vs. Errol Spence Jr. online

You can watch Kell Brook vs. Errol Spence Jr. on sho.com.

Kell Brook vs. Errol Spence Jr. card

Kell Brook vs. Errol Spence Jr. is the only fight on the telelvised portion of the show.

Steven Muehlhausen is an MMA and boxing writer and contributor for Sporting News. You can find his podcast, Fight Club Chicago, and subscribe on iTunes, Soundcloud and Stitcher. You can email him at stevemuehlhausen@yahoo.com and can find him on Twitter @SMuehlhausenMMA.