Swank, who was present at the yet-to-open Almada restaurant in Mayfair to celebrate her role as the face of beauty house Guerlain's new Insolence fragrance, was in an ultra figure hugging black Dolce & Gabbana dress.
The Oscar winning actress said that despite good genetics, she still enjoys the result of working out.
"I really appreciate exercise because I think it's a great stress relief. I do this thing called power Pilates, which I love. love, love," the People quoted Swank, as saying.
However, the 33-year-old actress holds her genes responsible for her slender fitness.
"But ultimately it's Dad who gets the credit. I try and get out as much as I can but I think in the end I really have to give it up to my genes," Swank said.