She stepped on the object, which her office did not identify, on the beach in Hawaii last week and it apparently became lodged. The incident occurred prior to Biden’s two official events in Hawaii, her spokesman Michael LaRosa said.

President Biden will join the first lady for the procedure, which will take place at Walter Reed National Military Medical Center in Bethesda, Md.

“I’m going to find out in a minute. That’s why I’m leaving,” he said.

The first lady visited Hawaii on Sunday after going to Tokyo to lead the U.S. delegation at the Olympics.