Sebastian Stan Muscles Up While Strolling the Big Apple

Sebastian Stan listens to music on his earphones while strolling around town on Thursday (September 3) in New York City.

The 33-year-old actor was seen baring his buff biceps in a white tee and holding a hardcover book and his iPad mini.

PHOTOS: Check out the latest pics of Sebastian Stan

Earlier in the week, Sebastian was seen stepping out with his girlfriend Margarita Levieva and their dog.

Sebastian will be seen next in the upcoming sci-fi adventure movie The Martian, which starts Matt Damon as an astronaut presumed dead who gets left behind on Mars.