Michael Phelps is coming out of retirement, in a first step toward swimming at the 2016 Rio Olympics.
The 22-time Olympic medallist will compete for the first time since the 2012 London Olympics at a meet in Mesa, Arizona, on April 24-26.
USA Swimming said that Phelps is expected to join fellow Olympians Ryan Lochte and Katie Ledecky at the Arena Grand Prix at Skyline Aquatic Center.
"He's coming back, that's pretty definitive," said Paul Smith, CEO of Mesa Aquatics Club, hosting the Grand Prix.
"We're hopeful we're part of that story. It would be magnificent to have that, and him coming back is great for the sport regardless."
Phelps returned to training last fall and re-entered the U S drug-testing program.
He has completed his six-month waiting period to be eligible for competition by the U S Anti-Doping Agency.
Phelps turns 29 in June and is the most decorated athlete in Olympic history.
He captured 18 gold medals and 22 medals overall at the last three Summer Games and broke Mark Spitz's record for a single Olympics by winning eight gold medals at Beijing in 2008.