Bolt and Gay gunning for medals at the end of a busy summer
Triple Olympic champion Usain Bolt and close rival Tyson Gay will face each other in Brussels just three weeks after the World Championships.
Gay has the fastest times over 100m and 200m this season and his manager said: "It will likely be the 100m but it is confirmed they will race."
The pair are still to meet on the track this year but should go head-to-head in the 100m and 200m in Berlin next month.
Discussions also are under way for the two to race in Zurich on 28 August.
Bolt set world records in both sprint events at last year's Olympics, while Gay, the 2007 double sprint world champion, did not feature in either final in Beijing.
The American failed to qualify for the 100m championship race at the Games and did not compete in the 200m because of a hamstring injury at the US trials.
Injury concerns have hampered Gay's preparation for the Worlds - which start on 15 August - with the 26-year-old admitting to groin troubles after his 200m victory at the London Grand Prix last month.
Bolt cruised to victory in the 100m in 9.91 seconds at the same meet and would appear to be favourite for gold in Germany, despite Gay having clocked 9.77 for the 100m and covered 200m in 19.58 so far this season.
Jamaica's Bolt said before racing at Crystal Palace that he felt Gay could not beat him over 100m, while the American said he was "running on faith and that's more dangerous than anything".
However, Gay showed improving form and fitness last Friday, sweeping to a 100m victory at the Super Grand Prix in Stockholm in 9.79 - two-hundredths of a second slower than his world's best mark this season - set in Rome on 10 July.
The 100m World Championships final is on Sunday, 16 August at 2035 BST and Britain's Dwain Chambers, Tyrone Edgar and Simeon Williamson will also hope to be among the medals.
The Berlin crowd will be cheering on the 200m runners in the final on Thursday, 20 August, with Chambers and Marlon Devonish set for action.
European Under-23 200m champion Toby Sandeman withdrew on Wednesday because of a foot injury.