Hilary Duff thinks something's really funny while she bikes for charity.

While the rest of us try hard at maintaining our best Ice Cube face at the gym in an effort to ward off any eye contact whatsoever, Hilary Duff  thinks the stationary bike is the perfect time to let the LOLs out. The ever-adorable new mom and her sister, Haylie, were on hand for the Pedal on the Pier charity event in Santa Monica recently, and Hil must have seen the most hilarious ish right before this photo was snapped...because Haylie's all, "HILARY I DON'T UNDERSTAND WHAT YOU THINK IS SO FUNNY I'M DYING OMFG."

But who can blame Hilary? She has a lot to celebrate these days: She just had a really adorable baby with a really adorable husband and she posts photos of her little one on Twitter all the time. She's got it all, y'all! I'd be LOLing all day, too.

Photo credit: Pacific Coast News