Anthony Joshua beat Wladimir Klitschko at Wembley Stadium on April 29.
IBF-WBA world heavyweight champion Joshua (19-0, 19 KOs) made himself a global star with his stunning stoppage win over Wladimir Klitschko in front of 90,000 fans at Wembley Stadium in April.
Billy Joe Saunders beat Andy Lee to claim the WBO middleweight belt in December 2015.
After a dismal reign as WBO world middleweight champion since December 2015, Saunders (24-0, 12 KOs) finally seems motivated after moving to Sheffield to be trained by Dominic Ingle.
Any slim chance remaining of this fight happening evaporated when Brook lost his IBF world welterweight belt to American Errol Spence Jr. by 11th-round stoppage in May.