Rob Kardashian: "I'm aware that I'm fat"

Rob Kardashian arrives at the 2012 Miss USA pageant the Planet Hollywood Resort & Casino on June 3, 2012, in Las Vegas.

Isaac Brekken/Getty Images

Rob Kardashian, 27, says he's completely aware that he's "fat" -- and that's OK.

On Monday, the "Keeping Up with the Kardashians" star was photographed at Los Angeles International Airport (see picture here), prompting the Twittersphere to blow up with comments about his apparent weight gain.

Now the one-time trim reality star is speaking up: