Mila Kunis and Ashton Kutcher are ''over the moon'' about life as a family of four.

The happy couple married in 2015 and have three-year-old daughter Wyatt and 21-month-old son Dimitri together, and although it's been almost two years since their youngest tot was born, they're still relishing in joy of being parents to a beautiful brood.

A source told People magazine: ''They married their best friends and have continued to grow in their relationship by openly communicating and keeping their heads out of the clouds.

''They are real people and have found true love, trust, friendship and honesty. They are a great example for others to follow.

''Both of them wanted to be parents for quite a while before they had children, and they are still over the moon.''

Mila - who turned 35 on Tuesday (14.08.18) - and 40-year-old Ashton first met when they starred together on 'That 70s Show', where a then 19-year-old Ashton was Mila's first kiss, when she was just 14.

The pair never dated each other until much later, with the 'Bad Moms' star going on to have a lengthy relationship with Macaulay Culkin, and Ashton marrying Demi Moore in 2005 before their divorce in 2013.

Mila and Ashton then reconnected, and originally had planned to keep their relationship as a simple hook up, before realising they had feelings for one another.

Last month, the 'Family Guy' actress said: ''I did a movie called 'Friends With Benefits'. He did a movie that was very similar called 'No Strings Attached'. We lived out movies out. We were just like, let's just hook up. Let's have fun. We're both single. We both trust each other. Everything's great.''

Mila attempted to call the deal off after realising her growing feelings for the 'Jobs' actor, after he told her about another girl he had been seeing.

She added: ''I felt like I got punched in the gut, literally overnight. I was like, you know what, I actually care about you. I don't want to mess anything up so I'm just going to walk away before it becomes too much.

''And he was like, 'Got it.' And the next day, he showed up to my house and was like, 'Move in with me,' and I said, 'Okay.'''