The former Public Enemy star was seemingly thrilled to meet Cyrus at the event after bumping into her backstage, but shouted, "Gwen Stefani. Wow... How you doing? Oh my god, nice to meet you."
An embarrassed Cyrus, who recently dyed her hair platinum blonde like Stefani, was too polite to correct his error, and after they parted ways the rapper walked away yelling the No Doubt frontwoman's last name.
Flavor Flav's handlers then alerted the 53 year old to his mistake, and the stunned reality star's jaw dropped as he exclaimed: "That's Miley? No. That's Hannah Montana? Y'all (are) stupid!"
He then ran back to Cyrus to right his wrongs, and approaching her again, he said, "Do me a favour, smack me."
The pair then hugged it out and the incident was all captured on camera by Tmz.com.