Just two days after his daughter was born, Ashton wrote the following message on his website aplus:
"Mila and I would like to welcome Wyatt Isabelle Kutcher to the world. May your life be filled with wonder, love, laughter, health, happiness, curiosity, and privacy."
He also shared the first photo of newborn Wyatt - but there was a touch of mystery around his announcement.
Ashton posted the picture along with seven other anonymous baby photos (including a llama and a dog) and said:
"Can you guess which one is ours, or does it really matter? All babies are cute."
Very true and very clever. Here are just two of the baby pics (see all eight photos here.)
Ashton later added another note to his Facebook page.
"Here's your baby photo," he wrote. Well, one of them is. Now can the helicopter please stop hovering over our house, there is a baby sleeping inside! And she's super cute."
Whichever baby Wyatt is - she is definitely "super cute!"
Wyatt was born 30 September at the Cedars-Sinai Medical Centre in Los Angeles.
A source confirmed the news to US Weekly and said Ashton and Mila had a "healthy baby girl" and "are so happy!" after the birth of their first child together.