Mila Kunis once accidentally greeted her UPS delivery driver whilst topless.

The 34-year-old actress has admitted the delivery driver got more than he bargained for when he turned up to the star's home on a particularly hot day to find her tending to her newborn son Dimitri - who is now 11 months old - completely shirtless.

She said: ''My UPS guy is really sweet, and I've had him for years, and he always [just] drops off the package, but you can see him through the glass window. At one point, I was just shirtless, because I was hot. I was just with my baby, and I was three days postpartum, so it still was like [I was] pregnant.

''I was just like, 'Hey.' Didn't even think about it, naked, skin-to-skin with my baby. And he just puts the package down and looks up. And I was like ... I didn't even care.''

And the 'A Bad Mom's Christmas' star - who has Dimitri and daughter Wyatt, three, with her husband Ashton Kutcher - insists she wasn't left ''embarrassed'' by the awkward encounter, as she thinks the unnamed driver was more shocked than she was.

She added: ''[I] wasn't really embarrassed, [I] felt more bad for the UPS guy. I was like, 'This is not nearly what you thought you were walking into.'

''I think he may have been like, 'Oh, that's what they look like?' You know, a nursing breast and a [non-nursing] breast. It's just two very different boobs.''

Mila also admits she was ''in bliss'' during the blunder, as she was too focused on her newborn baby to find the unusual meeting mortifying.

She told People magazine: ''I guess that could have been an embarrassing moment, but I was in bliss. I was like, 'My baby!'''