A man attacked him at around 2.30am outside The George, calling him a "queer", before running off.
Brendan (48) said that his Facebook page has been flooded with messages of support after he revealed what happened.
And he told RTE's Liveline programme that more than 50 gay people came forward to tell Brendan that they too have been assaulted or verbally abused in towns across Ireland.
"The amount of kind wishes is mind blowing, thank you so very much," he wrote. "But more alarming is the number of similar stories people have sent me. Be strong, stand tall, mince and kiss whoever you want."
Courtney went ahead to attend the star-studded affair of the Irish Film and Television Awards (IFTAs) on Saturday evening sporting a black eye.
"It is ironic that it happened before probably the most public night of my life," he said.
"Shockingly, we have a gorgeous, cosmopolitan city, but it is still alarming and bizarre that this sort of thing still happens."
The RTE star has said he will report the violent, homophobic assault to gardai but he failed to report it at the time as he was so stunned and it happened so quickly.
"I'm very lucky that this has been my first brush with anything like this but it isn't uncommon," Brendan said.
The Dubliner said that he is always careful in the city centre but admitted that he was shaken by the unprovoked attack.
"How do you prepare for someone running up to you out of nowhere and hitting you straight in the face?" he said. "I felt very threatened.
"I think he was probably motivated as much by the fact I'm on television as the fact I'm gay, because there were loads of gay people there at that time."
The stylist's Facebook page had dozens of messages of support from fans.
"You are a real hero to come out on air about the attack, brave and courageous," said one supporter. "You came across very well & shame on the attacker."
"Absolutely appalling unprovoked violence," said another. "Let's hope this matter of violent crime can be addressed to visiting politicians canvassing the various towns as it cannot be allowed to go unpunished."