But Whitney hasn't lost her fashion mojo - she was judging the Vans Custom Culture contest in New York, so it was only natural she wore her Vans plimsolls.
Whitney was joined by actress Emma Roberts as she co-judged the contest, where high school students designed a custom pair of Vans to win a $50,000 prize.
The fashion designer looked more ready for a walk in the park than a special event, as she donned a baggy grey marl dress and red leather jacket.
But despite her casual outfit, Whitney won us over with her fabulous orange lippy.
Satsuma lips are a huge trend this summer - we've already spotted Caroline Flack, Kimberley Walsh, and Kate Bosworth rocking them.
Pair with simple flicked eyeliner and tousled hair like Whitney, and let your bold pout do the talking!
What do you think of Whitney's outfit? Let us know by commenting below as the best comment across the site each week wins £50!