Adam Peaty's return to the global stage and Sarah Sjostrom's bid to burnish her record medals haul will give the world championships in Doha a vital boost at a meeting many of the top swimmers have chosen to sit out.
Breaststroke king Peaty has carried British swimming on his shoulders for a decade but the three-time Olympic champion has been sorely missed on the world stage in recent years.
Peaty skipped last year's championships in Fukuoka during a mental health break and missed the 2022 meeting in Budapest with a broken foot.
But the 29-year-old is set to take the plunge in the heats for the 100 metres breaststroke on the opening day of competition on Sunday.
World record holder Peaty has dominated the 100 breaststroke like no other, winning three world titles and back-to-back Olympic golds in the event at Rio and Tokyo.
He has designs on a "three-peat" at the Paris Games six months from now, and Doha may offer clues as to whether he still has what it takes.
China's Qin Haiyang, who claimed an unprecedented hat-trick of 50, 100 and 200 breaststroke titles at Fukuoka, is skipping Doha but Peaty will have a fight on his hands against world silver medallists Nic Fink, Nicolo Martinenghi and Arno Kamminga.
In addition to Qin, Doha will be missing a slew of other champions from Fukuoka with the Paris Olympics just around the corner.
American great Katie Ledecky has given up the chance to add to her six successive world titles in the 800 freestyle, while Lilly King and Ryan Murphy are also missing from the U.S. team's slimmed-down roster.
The US will have Kate Douglass defending her 200 medley title and Hunter Armstrong bidding to back up his 50 backstroke gold.
"I don't know quite what to expect overall but I would expect to see some fast swimming," U.S. national team coach Erik Posegay said.
"I do believe that there are some swimmers who see this as an opportunity to really post some great times, some great swims."
Australia have also left a raft of big names at home, including Olympic 200 and 400 freestyle champion Ariarne Titmus and 100 freestyle world champion Mollie O'Callaghan.
While Canadian young gun Summer McIntosh and rising Frenchman Leon Marchand are also skipping the meet, Sweden's Sjostrom is not passing up the chance to add to her crammed trophy cabinet.
Grabbing the 50 freestyle and 50 butterfly titles at Fukuoka, the 30-year-old leapfrogged Michael Phelps to become the most decorated individual swimmer in world championships history with 21 medals dating back to 2009.
She is set to defend both titles in Doha and also compete in the blue riband 100 freestyle.
With 13 titles at Fukuoka, Australia topped the medals table at Fukuoka ahead of the United States (seven) in a confidence boost ahead of the Olympics -- but the spoils are likely to be spread far and wide at Doha.
Australia head coach Rohan Taylor said none of his swimmers in Qatar would be keeping their powder dry for Paris.
"It's still a world championships," he said.
"Everybody's here to be perform at their best."