The TV presenter and her husband Trent Miller welcomed their first child, Ruby May Miller, on Thursday night.
Their friend Ben Fordham announced the news on the Today show on Friday morning, saying the parents were overjoyed.
“Little baby girl Ruby May Miller was born last night. She weighed 7.5 pounds [3.4kg] and is absolutely beautiful. Mum and baby are fantastic and dad is pretty happy too,” he said.
The couple kept the sex of their child a secret – from themselves and everyone else – throughout the 40-year-old’s pregnancy.
“I’ve always maintained that I didn’t want to find out. I just felt like it was one of the greatest surprises in life – a true legitimate surprise – there was no cheating,” she told Nine Honey last month.
“But Trent’s made up his mind it’s a girl.”
Turns out, he was right.
Maddern announced her pregnancy in November with an Instagram post of a teddy bear and booties, captioning the image: “Can’t wait for our new arrival in 2018 [with a baby emoji]”.
Planning on giving birth? Monique Bowley and Bec Judd discuss everything you’ll need for the first three days with a newborn, on Hello Bump. Post continues after audio.
At the time, she said her baby was expected in May (maybe that’s where the middle name came from?) – so she’s arrived a little early.
Maddern has previously said that she’s had “great” chats with Channel Nine about returning to The Footy Show, but hasn’t decided how much time she will take for maternity leave.
“I’m not going to rush back to work after four weeks,” she told Nine Honey.
“Hats off to the ladies who do that but I’m just going to take my time with this one.”