The couple, who have been together for five weeks, recently let the cat out of the bag.
On Tuesday, Michael gushed about his new romance on Instagram, saying he wasn't sure how he'd managed to "pull this off".
"I have tried to retrace my steps from a big night out, waking up thinking how did I manage to pull this off 😂.... Though I ain’t complaining lads 🍺" he wrote, alongside a number of photos of the couple.
"@kcosborne_ you have honestly changed my world for the better all jks aside 😘. PS @kcosborne_ wanna stay in tonight just the two of us?"
KC has been vocal about their new romance on her social media too, professing her "love" for Michael in one gushy post.
"I finally found my best friend 💘 @mickygoonan #lovehim" she wrote on Tuesday, alongside loved up pics of her and Michael.