51-Year-Old Flavor Flav CARDED at Liquor Store

2/23/2011 9:00 AM PST
He's been world famous for more than 20 years -- but 51-year-old Flavor Flav was forced to SHOW ID before he could buy cigarettes at a Las Vegas convenience store Monday night ... TMZ has learned.

We're told Flav asked to buy a pack of grape-flavored Swisher Sweets ... when the clerk asked Flav for identification proving he was of age.

Flav respectfully obliged ... and tells TMZ, "I wasn’t bothered ... I was flattered that she asked me for my ID" ... adding, "The woman was there doing what she had to do, her job.”