Mary-Kate and Ashley Olsen debuted on "Full House" when they were only nine months old, and in many fans' hearts, the twins will always be Michelle Tanner. However, despite the sisters' extremely similar looks that allowed them to share one role flawlessly, the Olsens are actually fraternal twins, not identical — here's how you can tell them apart.
Mary-Kate and Ashley have small differences in their appearances; for instance, Ashley has a freckle above her lip that Mary-Kate lacks. Ashley is also one inch taller than her sister and is right-handed, while Mary-Kate is left-handed, but the latter difference isn't really something you'd notice, unless you were looking for it.
Growing up from kids to full-fledged adults has also caused the twins to look different from each other. Ashley now has slightly fuller lips than her sister, and Mary-Kate has tried different hair hues such as red and brown, while Ashley kept her classic blonde hair, leading to the most obvious visual difference between the twins so far.