In a video posted to social media on Saturday morning, the 34-year-old insisted he was happy to step into the ring after only six weeks of preparation.
It appears an agreement has been sealed between the boxers for their unification showdown after Usyk, 36, accepted a 70-30 per cent split of the purse in Fury’s favour, on the condition a £1million donation was made to Ukraine’s fight against the Russian invasion.
“Today’s the first day of my training for the Usyk fight,” Fury declared on social media.
“I don’t need six months, four months and all that. I got six weeks and a week’s rest. Done.
“Happy days. And I’m gonna impose my world on this little sneaky m***********. Cannot wait. Rule Brittania.”
Wembley Stadium is booked for April 29 after talks to hold the fight abroad collapsed.
The undefeated Fury last fought in December, downing Derek Chisora to defend his WBC title, while Usyk required time off to recover from injuries he suffered when beating Anthony Joshua for the IBF, WBO and IBO belts last August.