The 30-year-old singer was barely recognisable when she stepped out make-up free for a quick stop with a pal at a Hollywood office building on Thursday.
However, Katy - currently dating fellow musician John Mayer - did add a touch of glamour to her ensemble with the addition of a pair of diamond studs and a stylish black handbag.
Her look was a far cry from the stunning outfits she wore at the Super Bowl and Sunday's Grammy Awards, where she turned heads in a variety of flattering looks.
and better than most pop girls 
