Celeb hair stylist George Northwood (who looks after the locks of Rosie Huntington Whiteley, Alicia Vikander and Alexa Chung) told Vogue that the habit is probably doing more harm than good.
"Never, ever brush in the morning,” George said. “For one thing it leads to frizz, and secondly there's always an element of mechanical damage. Use your fingers and you'll be able to feel out any tangles.”
And if you're super desperate: "Run a Mason Pearson brush across the hair's surface just once."
So how can you ensure you're not spooking your colleagues with a rendition of Cousin It? George recommends prepping the night before. If you're after a slick look, pull your completely dry hair into a tight, neat bun at the nape of your neck. In the morning just shake it out and smooth through an oil or serum to take care of any fly aways.
Plus that way you can hit the snooze button a few extra times, too.