Flavor Flav to Miley Cyrus — Nice to Meet You … GWEN STEFANI

And this week”s painfully cringeworthy award goes to … FLAVOR FLAV … who met Miley Cyrus backstage at the iHeartRadio Music Festival and was convinced she was GWEN STEFANI.

The video was shot Friday night in Vegas — showing Flav bumping into Miley backstage and getting really excited … blurting out, “GWEN STEFANI!!!”

Miley doesn”t correct him, she just smiles and gives him a hug. Then Flavor calls her Gwen again.

At that point, someone in Flav”s camp pulls him aside and tells him it”s actually Miley Cyrus.

At first, Flavor can”t believe it — but after the penny drops, Flavor tries to make amends … turning to Miley and saying, “Do me a favor. Smack me.”

Funny … Gwen was also there Friday night … looking NOTHING like Miley.