Tyson Fury sends contract to Anthony Joshua for Wembley showdown in September
Fury has not fought since retaining his title with a 10th-round stoppage of fellow Briton Derek Chisora in December.
Fury called off his proposed 'Battle of Britain' bout with two-time world champion Joshua last September, saying his countryman had not signed the contract before the deadline.
"... it's a fight that everyone wants to see including myself," unbeaten Fury said in an Instagram post on Friday.
"This time I'm not gonna make a million vids & keep putting pressure on. the ball is now on your side."
Earlier this year, Fury was scheduled to face Ukrainian Oleksandr Usyk, the IBF, IBO, WBO and WBA champion, in a unification fight but negotiations fell through in March.
Fury has 33 wins and a draw from 34 bouts, while Joshua has 25 wins and three losses in his 28 professional fights.
Joshua, who beat American Jermaine Franklin on points in London in April, has twice lost to the 36-year-old Usyk.