Not quite what we consider workout gear!

Anne Hathaway went on a Sunday walk with husband Adam Schulman and some pals, and the Oscar winner donned starry leggings and a denim button down that just happen to show off her much curvier physique!

The actress just celebrated her 31st birthday over the weekend with a yummy dinner at Mr. Chow's in Beverly Hills, and it was quite the star studded bash with guests like Sidney Poiter and Christopher Nolan.

The brunette beauty is currently filming Interstellar, which centers around a group of explorers who make use of a newly discovered wormhole to surpass the limitations on human space travel, so maybe her cosmic spandex choice makes sense after all!