The 39-year-old, who has welcomed the baby daughter with his fiancé Cailean, announced the details of his daughter's birth in a super sweet Instagram post.
Sharing a photo of himself and Cailean holding their daughter's hospital cart and pointing into the air with happiness, Mark announced that their little girl was called Layla and had been born on 1st October 2019!
He wrote, 'Baby Layla born safe & sound @ 7.27pm on October 1st 2019! We’re the happiest Dads in the world! ❤️👶🏻🇮🇪🌈 😘 x.' [sic]
Fans from all over the world rushed to celebrate Mark's news, and Australian singer Delta Goodrem - who's also the ex-girlfriend of Mark's former bandmate, Brian McFadden - also left a message of congratulations, simply writing some heart emojis and kisses.
Mark announced that he and Cailean were expecting a baby on his birthday back in May. In a now-deleted photo, Mark posted a picture of a baby scan and a babygro, writing, 'Thanks for all the Birthday wishes everyone, it really makes this my most special birthday EVER to let everyone know that later this year we will become Dads for the first time. This is the proudest moment of our lives and we are beyond excited to say it out loud!'