The Australian actress, 42, took to Instagram to proudly share the news along with an adorable first-look at her new addition.
Revealing that the baby girl’s name is Roycie Lillian, the tot can be seen wearing a pink onesie and unicorn slippers.
Her face is partially obscured with one hand - perhaps already fed up of her mum like most new parents taking endless photos of their newborns.
“Beyond proud to announce the birth of my first child, Royce Lillian, born this past week via surrogate,” the Bridesmaids star captioned her post.
“I can’t even describe the love I have for her, she’s a beautiful miracle! I am forever grateful to everyone who has been involved, (you know who you are), this has been years in the making…but particularly wanted to thank my gorgeous surrogate who carried her and birthed her with such grace and care.”
Wilson continued: “Thank you for helping me start my own family, it’s an amazing gift. The BEST gift!!
“I am ready to give little Roycie all the love imaginable. I am learning quickly…much respect to all the Mums out there! Proud to be in your club.”
Among those rushing to offer their congratulations and well wishes in the comment section was Wilson’s girlfriend Ramona Agruma.
The fashion and jewellery designer responded to the post with three red love heart emojis.
The couple have been in a relationship for seven months and over the weekend denied reports that they had got engaged.