Jack and Courtney, who starred on Love Island in 2021, took to Instagram on Monday to announce the new arrival.
"Penelope June Millar. A love so magical words cannot describe! 10/11/23," they wrote alongside three photos of their daughter.
Jack's MAFS 'wife' Domenica Calarco commented on the snap, writing, "WELCOME BABY GIRL!"
"AHHHH BURSTING AT THE SEAMS!" MAFS star Ella Ding added.
"Crying I love her so much," one follower wrote.
"Omg congratulations, she's absolutely beautiful," another said.
"This is beautiful, and the name is amazing, enjoy," a third added.
Jack and Courtney moved in together in January this year after meeting and falling in love last year.
They announced the pregnancy in May with a sweet video, writing, "Overjoyed to share our magical secret with you."
'Love of my life'
They then stayed in contact and had their first date in June last year when Jack went to the Gold Coast for the Logie Awards.
“It was going swimmingly, it was all just very natural,” he detailed. “And then she came down to Sydney after that and we went down to the snow.
“I don't know whether you'd call that snow trip the second date, but she stayed for two weeks and five days in was the first time I told her that I loved her. We were a little bit drunk, we had a few little wines and I was just like, ‘I love this girl’.”
Jack went on to describe Courtney as “the love of my life” and said their relationship is what he is most thankful to MAFS for.
“It's not that the show placed us together, but it definitely gave me the avenue to be in the same circles that I wouldn't have been in,” he remarked.
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