"Your man should not upstage you," Kutcher advises. "He is there to highlight you."
The actor, 29, offers that gem, among others, in an essay on fashion tips that appears in the September issue of Harper's Bazaar, on newsstands now.
In the essay, Kutcher endeavors to help couples struggling with how to dress and offers the male point of view when it comes to sprucing up.
"Guys don't like to be told they look nice, pretty, or cute or that they clean up well," writes Kutcher, who's been married to Moore, 44, since 2005.
"We want to feel dirty, rugged, and, most important, that you feel safe when you are in our company," he continues. "So when your guy finally tries on something that you like, tell him that he looks like James Bond or Tony Montana."
Adds Kutcher, "Feel free to be even more vague than that: 'Wow, that suit makes you look like that hot football player!' Trust me, say any of this and you won't be able to get him to take the damn suit off."
"When it comes to getting dressed, men are a little bit more important than handbags but less important than shoes," he writes. "At any rate, we are merely accessories."
Kutcher offers one final fashion don't: dressing alike.
"Make sure the look isn't too matchy-matchy," he cautions. "Your best bet is to match the man gear to that great new Balenciaga bag that you're planning to carry. If your bag works with your outfit, so will he."