Boxer Carl Frampton gave his backing to leisure centre staff from the Shankill and Falls who joined forces over the weekend to voice their opposition to proposed job losses across the city.
Some 49 jobs are under threat by leisure centre operator GLL (Greenwich Leisure Limited), which took over the running of leisure centres from Belfast City Council three years ago.
A crowd carrying placards marched to the peace line at Northumberland Street.
The cross-community rally follows a meeting last week organised by People Before Profit councillor Matt Collins in Belfast City Hall, attended by a large group of leisure staff and trade unionists from across the city.
Mr Collins said: "These job losses are the latest in a series of attacks on our leisure services. Workers are rightly angry that their terms and conditions are being eroded.
"It was very significant that staff came together from across the divide to oppose these attacks on our services."
Unite regional officer Michael Keenan said: "Since the handover we have lost 118 former Belfast City Council workers, replaced by casual and poorly-paid workers employed on GLL contracts."
In a statement GLL said it was a charitable social enterprise which was "in the process of implementing a modernisation programme and this includes the restructure of the leisure services it provides within Belfast".
It added: "This is a hugely positive project, which will improve employment opportunities in the city with the creation of 50 totally new jobs.
"While some historic staff roles will change, the restructure offers fantastic career development prospects within the leisure industry."