Ashton Kutcher reportedly refers to Mila Kunis as his "little wife".

The long-time friends are rumoured to be in a relationship, although neither have confirmed their romance.

Ashton - who split from wife Demi Moore in November last year - is said to be "totally into" Mila, and already has a serious pet name for the stunning star.

"He's calling her his 'little wife,' which is cute but kind of odd since he's not divorced yet," a friend of the actor told US publication Life & Style.

Mila is reportedly enjoying her new relationship with Ashton. The actress - who starred alongside the Hollywood hunk on That 70s Show - is happy to take things one step at a time though.

"Mila's playing it cool with Ashton," Mila's friend told the magazine. "She's not pushing for a ring."

The 29-year-old beauty recently revealed her views on walking down the aisle.

"I'm not sure about marriage," she previously explained. "I see no need. I'll be with somebody because I want to, not because a piece of paper tells me I have to."