Moore came under fire last week after pictures of the star's toes popping out of her shoes during Cannes Film Festival went viral on the internet.
When Fallon asked her about the incident, Moore said she didn't realize her toes were out until she got home and saw the pictures online.
"I didn't feel a thing -- not a thing," she said of the incident. "I felt fine! I was just walking along, like, 'Hiiiii, I'm at Cannes' and my toes are hanging off [my shoes]!"
Later on the actress joked about what she did to prevent this "Toemageddon" incident in the future.
"I did what every reasonable person would do," she told Fallon. "I needed to prevent this from happening again, so I cut my toes off."