Gwyneth Paltrow "cannot function" in untidy places.
The 44-year-old actress goes on a "cleaning frenzy" when she is feeling upset or stressed and can't sleep if she knows there are still chores to do.
She admitted: "I cannot function if there is a physical mess around me. If everything is falling apart, I go on a cleaning frenzy...
"I cannot go to sleep with dishes in the sink."
Gwyneth - who has children Apple, 12, and Moses, 10, with ex-husband Chris Martin - is close friends with Beyoncé and thinks people are constantly astonished by how "shy" and low-key the pop superstar is in her everyday life.
Speaking of her pal - who has four-year-old daughter Blue Ivy with husband Jay Z - Gwyneth told America's Harper's Bazaar magazine: "If you met her and you didn't know who she was or what she did, it would be inconceivable to you that she was Beyoncé.
"Some really famous people, even when they're off-duty, have this energy that is sort of overpowering.
"She does not have that. She is so dialed down. She's the sweetest mother. She's very shy.
"You would not believe she is Beyoncé Knowles. You would be like, 'No, that was not her.' And that's why when I see her perform, I'm like, 'Oh, s**t, I forgot.' "
Despite her own fame, the 'Mortdecai' star insists she can still be a "normal mom" and go unrecognised most of the time.
She said: "I've learned to navigate it. If I'm somewhere where there are a lot of tourists, then I'm asking for it. But if I go to the market or I'm back-to-school shopping with my kids, it's not a problem.
"Some people ask for pictures, but it's completely fine. I'm able to be a normal mom for the most part. I'm in (clothing store) Brandy Melville like all the other moms.