The Memorial Van Damme in Brussels, the fourth meeting of the coronavirus-hit Diamond League athletics season, will be staged behind closed doors on September 4, organisers have said.
Officials explained that as a decision has still not been made by the Belgian government on whether fans can return to stadiums from September, they were erring on the side of caution.
"The health and the safety of the spectators, the athletes and the staff are our highest concern and priority," Brussels meeting director Cedric Van Branteghem said in a statement on Tuesday.
"From a practical point of view the best thing to do was to decide now and to clearly communicate with our fans and our audience on ticketing issues."
The Diamond League season is set to belatedly get underway on August 14 in Monaco, but meetings in Eugene, London, Paris, Rabat, Gateshead and China have all been cancelled.
The Brussels meet will feature four-time Olympic champion Mo Farah and Belgian Bashir Abdi attempting to break the track hour record set by Haile Gebrselassie in 2007.
Sweden's pole vault world record holder Armand Duplantis will also compete at the King Baudouin Stadium.
Olympic heptathlon champion Nafissatou Thiam is set to go head-to-head with rival Katarina Johnson-Thompson, the world champion, in a triathlon featuring the 100-metre hurdles, high jump and shot put.