She posted a picture that Ashton had originally tweeted of the pair supporting their American football team the Chicago Bears and wearing the team colours orange and blue. The caption simply said: "Ashton and I#proudparents".
Ashton and I 💏 #proudparents
Mila describes herself on the site as 'Mom/Actor/Model'. Despite having only four posts the account already has over 6,000 followers.
Immediately after Wyatt's arrival, the new parents teased fans with several pictures of babies inviting them to guess which was their little girl. To confuse matters even more cheeky Ashton also posted pictures of a lama and a dog.
Ashton returned to work about a week ago, filming a live YouTube video on a tablet he has created in collaboration with Lenovo. In the video he made a reference to the birth of his daughter, saying: "I'm excited to be here to introduce my other new baby, the Yoga 2.
"My kid's only eight days old, so [she's] not quite reading yet, but when we get there, I'm sure I'm going to project bedtime stories all the time."