Ashton Kutcher blames Adele for his moustache.
The 41-year-old actor has been sporting the facial hair for some time and explained it was a result of his wife Mila Kunis misinforming him about the dress code for the 'Hello' hitmaker's birthday party.
The 'Black Swan' actress had told Ashton the theme was 1970s New Year's Eve so the former 'Punk'd' star thought he'd fit right in once he trimmed his facial hair.
He told 'Tonight Show' host Jimmy Fallon: "I'm looking in the mirror and I've got a beard going and I'm like, 'Oh, I'm going '70s 'stache. It's gonna happen.'
"I whittle everything down and it's thin. I mean, it's a high school boy trying to grow a mustache thin. But it looks great for the party."
But Ashton realised his mistake as soon as he got to the party - and didn't want to admit his gaffe.
He said: "I look like Burt Reynolds from 'Boogie Nights'. What are you gonna be like, 'I got the decade wrong?' So I'm just playing it off like this is how I'm doing it these days. And I'm like, 'What's up Jay-Z, yeah this is my thing now!' It was really awkward."
To pay back his wife - who wore a "timeless" jumper for the party" - Ashton vowed to keep his moustache.
He said: "This is for real life. It's kind of crazy. I never intended to have this. I don't think I'd look good with it, but I'm keeping it...
"It's a spite 'stache. This is payback. It's a full blown spite 'stache."
But it seems his act of "spite" has backfired because the 36-year-old actress - with whom he has daughter Wyatt, four, and son Dimitri, two - has grown to like his facial fuzz.
Ashton added: "She likes it now. So now I can't get rid of it."