Mila Kunis thinks Ashton Kutcher and Demi Moore had a ''normal, real relationship''.

The 34-year-old actress - who married the former 'Punk'd' host in 2015 - has defended her husband's relationship with the 'Indecent Proposal' star and their 15-year age gap, saying they were not discernibly different to most couples.

She said: ''They had, like, a normal, real relationship.''

The 40-year-old actor - who was married to 55-year-old Demi between 2005 until 2013 - helped to raise the actress' three daughters, Rumer, 29, Scout, 27, and Tallulah, 24.

Despite the relative closeness in their ages, Mila insisted Ashton ''loved'' all of the girls, whose father is fellow Hollywood star Bruce Willis.

She told Marc Maron's 'WTF Podcast': ''They had three kids they were raising. It was, like, a normal life ... Yeah, he was younger, but he loved those kids.''

In fact, Ashton - who became their stepfather - has remained in touch with Rumer, Scout, and Tallulah in spite of his divorce from Demi.

Mila and Ashton started dating a few months after he split from Demi, and the actress recently admitted they were ''crazy neurotic'' about keeping their relationship a secret at one stage.

The 'Spy Who Dumped Me' star - who has daughter Wyatt, three, and 20-month-old son Dimitri with Ashton - confessed to being overly-protective of their relationship when they first started dating in 2012.

She shared: ''We were crazy neurotic about keeping it a secret, probably to a massive fault where we alienated so many friends, I'm sure.''

The loved-up couple previously worked together on the sitcom 'That '70s Show', and Mila revealed she felt a spark during their first real-life kiss.

She said: ''I'll tell you this - while I was single I never spent the night at another guy's house. This was the first time that I spent the night at the guy's house.''