Rising Australian welterweight boxer Jeff Horn needs to drop 4.5kg in a matter of days to make the weight for his crunch clash with German Rico Mueller in Brisbane.
Victory on Friday is likely to set the undefeated Horn up for a shot at Kell Brook's IBF world title, which the Brit is expected to vacate soon ahead of a move to the middleweight division.
Horn, 28, is confident he'll have no trouble losing the weight and is certain he'll still have the energy to overcome Mueller, who has lost only one fight in his career and not once in the past six years.
"It's all basically fluid. I'll cut down a little bit of food. It's never ideal to lose that much weight," Horn said on Tuesday.
"But as long as I'm not at that dehydrated state for too long I can put it straight back in. Hopefully on Thursday and Friday I'm feeling good."
Trainer Glenn Rushton said it shouldn't be taken as a sign Horn is in any way out of shape - he's leaner and stronger than what he was when he sent American veteran Randall Bailey into retirement with a seventh-round stoppage back in April.
"It is a bit to drop but if we've got to drop the undies at the last minute, whatever he's got to do, he will do," Rushton said.
"We've never failed making weight yet, Jeff's very professional."
Horn is currently ranked No.3 in the IBF world rankings, with American Errol Spence Jr. the only man ahead of him in the queue for a world title bout.
The IBF is set to order Brook's mandatory defence of his title against Spence but it's not anticipated the bout will actually go ahead.
Before thinking about belts, however, Horn must first account for Mueller, the 28-year-old who has never been stopped in his career.
Rushton described Mueller as a typical defensive counter-puncher.
"He'll block a few and then he'll unleash on you. We've got to be mindful of that," he said.
"I've studied him very, very well. Jeff leaves that up to me of course. We know exactly how to beat him and we've just got to execute."