Oleksandr Usyk begins his bid to become a two-weight world champion tonight when he makes his heavyweight debut against Chazz Witherspoon.
The Ukrainian stopped Tony Bellew last year to become the undisputed cruiserweight world champion and has taken 12 months to build into the bigger weight.
He was initially due to face Tyrone Spong in Chicago tonight but an adverse finding in a drug test saw him replaced by Witherspoon.
Usyk is expected to have little trouble with the American as he sets his sights on bigger fights in the future.
Here is everything you need to know about tonight's bout...
Fight time
The fight will start at around 4am
TV channel
The fight will be shown on Sky Sports Action with the programme starting at 2am
Live stream
The fight can be streamed on the Sky Sports website or on Sky Go
Undercard
Dmitry Bivol vs Lenin Castillo
Jessica McCaskill vs Erica Anabella Farias
Charles Conwell vs Patrick Day
Joshuah Hernandez vs Giovanni Mioletti
Anthony Sims Jr vs Morgan Fitch
TJ Doheny vs Jesus Martinez
Movladdin Biyarslanov vs Tyrome Jones
Otha Jones III vs Eric Manriquez
Reshat Mati vs Norfleet Stitts
Jenna Johlin Thompson vs Summer Lynn
Odds
Usyk 1/100
Witherspoon 33/1
Draw 50/1
Latest news
David Haye believes Oleksandr Usyk is ready to be thrown in with the best heavyweights in the world.
The former unified cruiserweight champion makes his debut in boxing's premier division against late-replacement Chazz Witherspoon on Saturday.
And Haye - who was world champion at both weights - has backed the Ukrainian to be a roaring success.
"Going into this weekend's fight I feel Oleksandr Usyk is a genuine world heavyweight title contender," he said.
"Anybody who has unified all the belts in one weight can automatically step up to the weight above and slide into the top five or top 10, particularly if you were a long reigning champion.
"Although he has not yet achieved anything in the heavyweight division, he can still be considered in the top 10 in the world.
"The reason for that is an awful lot of the heavyweights are, indeed, fat cruiserweights. If you stripped off the majority of body fat from Andy Ruiz Jr, he wouldn't be that much higher than the cruiserweight division.
"If you put four stone of body fat onto Oleksandr Usyk, he'd still be a great fighter, but it wouldn't make him more of a heavyweight.
"So, I think Usyk shouldn't bulk up too much but, instead, use his speed and athleticism to become a success."
