Chris Eubank Jr will be fined $500 000 after hitting the scales half an ounce over the weight limit for Saturday's long-awaited fight with fellow-Briton Conor Benn at London's Tottenham Hotspur Stadium.
Benn came in lighter than expected at 156.4 pounds with the limit for the 12-round Ring Magazine middleweight bout set at 160lbs.
Eubank was 160.05 lbs at the second attempt at weighing-in behind closed doors at a London hotel.
Both boxers have agreed a rehydration clause that bars them from gaining more than 10 lbs between Friday's weigh-in and a further check on Saturday morning.
The pair will come face-to-face at a ceremonial weigh-in later on Friday.
Eubank, 35 with a 34-3 record and 25 knockouts, has previously fought at super-middle while Benn, 28 and unbeaten in 23 fights with 14 knockouts, has been mostly a welterweight, two classes down.
Eubank is the IBO middleweight champion and has already been fined 100 000 pounds ($133 210) by the British Boxing Board of Control for slapping Benn with an egg at a press conference in February.
The fight, between the sons of former world champions and arch-rivals Chris Eubank Sr and Nigel Benn, was called off in 2022 when Benn tested positive for trace amounts of fertility drug clomifene.
The World Boxing Council cleared Benn of intentional doping in 2023, saying a "highly elevated consumption of eggs" was a reasonable explanation for the failed tests.
The pair appeared together at a press conference on Thursday, with Eubank speaking of the pain of his brother Sebastian's death and his difficult relationship with his father.
"These things are what pain is to me," he said. "The weight cut, the rehydration clause, these are all things that are not an issue, that are not important."
Eubank Sr has called the fight a circus and his son a 'disgrace' for smashing the egg in Benn's face.