Reese Witherspoon shopping sunglasses sweats high tops sneakers hat mustache tee I'm Not A Plastic Bag

Reese Witherspoon doesn't always dress for success when she steps out of the house!

Of course, this is her new favorite tee and those sweatpants look awfully comfy ... in fact, the whole outfit is almost identical to the one she wore last month!

The Oscar winner was snapped post-workout in Santa Monica yesterday afternoon, and she gave us a quick smile before stopping to grab a package on her way home.