The Radio 1 presenter took to Twitter to announce the happy news, revealing that she and her partner - fellow DJ Toddla T - welcomed their latest addition on Friday 6th January.
She told her 726k fans that their baby arrived 12 days earlier than expected, and it seems they're very much enjoying spending time together as a new family of four: 'Our baby was born last Friday, 12 days early and in 2 hours.
'We're basking in snuffly new-born baby love and feeling very grateful @TODDLAT'
Our baby was born last Friday, 12 days early and in 2 hours. We're basking in snuffly new-born baby love and feeling very grateful @TODDLAT— Annie Mac (@AnnieMac) January 11, 2017
There's no news on the sex or the baby name the couple have opted for yet. Annie and her partner Toddla T, real name Thomas Bell, also share a three-year-old son who was born in May 2013.
Fans been quick to congratulate the mum of two on Twitter, replying to her sweet birth announcement. One commented: 'Congratulations! A great start to the new year! God Bless! 🎉' and another added: 'fantastic news. Delighted all are happy, healthy & basking in snuggles ❤️'
The DJ even received messages of congrats from some of her celebrity friends! Singer Jack Garratt commented: '@AnnieMac @TODDLAT all my love and good health to you and the growing family!! XXX'.
Annie's pregnancy reveal was unusually low-key for a celebrity announcement. The 38-year-old posted the news on Twitter back in August 2016, explaining that she was disappointed not to be able to attend Bestival because she was expecting.
It's the first time I will ever miss it. I am very sad. Cutting down on gigs because I'm pregnant X https://t.co/IpYM0Njbld— Annie Mac (@AnnieMac) August 18, 2016
She told fans: 'It's the first time I will ever miss it. I am very sad. Cutting down on gigs because I'm pregnant X'
The mum-of-two has been keeping her followers up to date with her pregnancy, sharing some sweet snaps of her growing bump on Instagram.
Annie's latest photo, posted two weeks ago, shows her son resting on her pregnant tummy, simply captioned 'bellow pillow'.
Congratulations to the new family of four!