The couple glammed up for the special occasion with Conor fairly poured into the eye-catching outfit while Dee went for a more demure display in a pink mini dress, which was adorned with a blue print and numerous gems.
The MMA star (33) and his 34-year-old fiancée grinned for the cameras as they attended the bash which was held on the rooftop of the five-star Hôtel Martinez.
Under the purple, Conor wore a formal white shirt complete with a bowtie, and he teamed his jacket with tailored trousers and velvet shoes.
Meanwhile, Dee put her pins on display in a pair of simple gold heels while carrying her belongings in a coordinating bag.
The couple, who became engaged in 2020 after 12 years of dating, were in high spirits as they were captured sharing a giggle as they arrived.
The Notorious who has been hitting the gym ahead of his return to the Octagon, enjoyed some quality family time earlier this month when he and Dee celebrated the 5th birthday of eldest son Conor Jnr.
McGregor and Devlin have two other children together – daughter Croia, three, and son Rian, one.
As for McGregor’s fighting career, he is now preparing to make yet another comeback following last July’s defeat to Dustin Poirier.
In the meantime he has been engaged in another series of late-night ramblings, claiming in the most recent one that his “left hand is a Glock” in a series of bizarre tweets.
The UFC star took to Twitter on Tuesday evening to share his thoughts, where he started off by telling his followers that he’d beat anyone who went up against him in a fight.
“I feel like I could do you’s (sic) all in. Handy. Any list,” the Dubliner said.
“I hit you, I change you,” he then wrote as he shared some photos of him having a stare-off with the camera.
He added: “And I’m chomping at the bit to see you different.”
McGregor then began to tease his plans for returning to the Octagon this year after spending the past year recovering from his injuries sustained during his fight with Dustin Poirier last summer.
In his next few tweets, he said: “The Mac Daddy back in action,” followed by “Sitting on a billion, plotting a killing.”
“The date of my return is…” he hinted, but instead of naming a date for his next fight, he said: “Tick, tock, my left hand is a Glock.”
Next, the Notorious shared a photo inside the office of his Irish firm McGregor Sports and Entertainment, where he held up a phone a pretended to laugh maniacally.
The caption simply read: “Hahahajaja (sic) construction.”
But his peculiar social media posts didn’t stop there, as teased the date of his UFC return for a second time but then left fans hanging.
"My next fight is…” he said, before calling on those who want to fight him to come forward: “If you want a knock off me step up and say your piece. I’m still picking who.”
His rival Jake Paul, who has had a history of online spats with McGregor, poked fun at the Crumlin native by sharing a photo of him looking haggard with dark circles under his eyes.
McGregor added: “Just kidding, I well know who. When. What weight. Where. How it goes. Everything. I see dead people.”
He also shared two snaps from his gym in France, one showing the street outside and another of him posing in front of sign, which he captioned: “Late night hustling. I run companies like no other” before signing off for the night.