Hillary Clinton was delivering a keynote speech when, suddenly, what she thought was a bat fly across the air.

It was no bat, it was an athletic shoe and it was thrown by a member in the crowd.

Clinton was surprised but remained calm, even cracking a few jokes during her speech in Las Vegas.

"Is that somebody throwing something at me?" Clinton said after the object flew past her on the stage at the Mandalay Bay resort. "Is that part of Cirque de Soleil?"

The woman walked up to the first few rows of seating, threw the shoe and dropped some papers on the ground before walking out of the room with her hands in the air. The woman wasn't supposed to be inside the room where the speech was being delivered.

Security officials caught up to the woman. She did not explain why she threw the shoe to reporters. Reporters were not allowed much time to ask her questions before security ushered them away.

According to U.S. Secret Service special agent Brian Spellacy, the woman will be charged and is currently in custody.

The last famous shoe throwing incident occurred in 2008 when George W. Bush ducked two shoes thrown by an Iraqi journalist in Baghdad.

Clinton was not injured in the incident.