The ex-wife of Tom Cruise was also making a very peculiar facial expression.
Katie's brown tresses were piled into a messy bun on top of her head where several tendrils of hair hung down loose, and still sweaty from class.
But the mother-of-one's outfit looked effortlessly chic as she donned a breezy off-the-shoulder dress with intricate lace hem.
Katie paired her sweet dress with strappy brown sandals with a practical block heel, she carried a pair of Converse sneakers with her in case she wanted to make a comfy change.
The Logan Lucky star glitzed up her look with a shimmered necklace and several bangles.
The actress - who has 11-year old daughter Suri from her marriage to Tom Cruise - kept a roomy handbag in a dusty pink hue by her side.
Before her workout, the The Kennedys star arrived at the studio looking more polished, wearing her short tresses down while masking her face with tortoiseshell sunnies.
The Dawson's Creek alum is currently in Montreal shooting The Gift opposite Patrick Stewart.