The Girls star recently recruited celebrity fitness trainer Tracy Anderson to help her get into shape, and Dunham has been posting her progress on Instagram.com.

In her latest post, Dunham showed off her noticeably slimmer frame, and explained to her followers why the new exercise has helped her in more ways than one.

She wrote, "Promised myself I would not let exercise be the first thing to go by the wayside when I got busy with Girls Season 5 and here is why: it has helped with my anxiety in ways I never dreamed possible.

"To those struggling with anxiety, OCD (Obsessive Compulsive Disorder), depression: I know it's mad annoying when people tell you to exercise, and it took me about 16 medicated years to listen. I'm glad I did. It ain't about the a**, it's about the brain.

"Thank you @tracyandersonmethod for showing me the light."