Fans claimed he disrespected his partner of nine years, Dee Devlin, by cosying up to Rita Ora at the British Fashion Awards in a set of pictures she captioned "date night".
Following the scandal on Tuesday (5 November), 29-year-old Irish boxer McGregor is trying to prove to fans that he hasn't been affected by the social media uproar.
During a raucous night out at London's Cirque Le Soir nightspot in London – without Devlin and their baby son Conor Jr – McGregor gave a shout-out to the 27-year-old Anywhere hitmaker to fellow partygoers.
It followed his retweet of Ora's "date night" post which caused a stir among fans. One user told him: "You've got a fine Irish steak at home mate. No need to ruin it with a McDonald's."
The boxer was filmed grabbing the microphone at the nightclub and yelling a public tribute to the much-criticised singer. "Shout out to Rita Ora!" he called to a cheering crowd.
A clip obtained by MailOnline of the bleary-eyed boxer shows him standing behind the DJ decks and flashing a cheeky grin before tapping his chest.
McGregor appears to be revelling in the attention, despite many feeling sorry for his childhood sweetheart Devlin, who has stuck by his side and supported him throughout his career.
After the public slammed her as "Becky with the good hair" and a homewrecker, Ora shared the first snap of herself and boyfriend of over one year, Andrew Watt, on Instagram.
Fans were left unconvinced by the random public display of affection. One follower said: "As if this is gonna help."
Another said: "Now this is getting desperate".