(Twitter/@KimKardashian)

Kim Kardashian has the most famous booty in the world and she's not afraid to show it off.

The reality star posted a photo of her famous, sexy curves in a teeny bikini on her Instagram account Thursday. The photo, she insisted, was not digitally altered.

"No filter, no Photoshop," she tweeted alongside the photo.

SEE MORE: Photos of Kim and the Kardashian Clan

The star claims to stay thin by working out a few days a week and eating healthy.

"I still hit the gym most days to tone up," she told Closer magazine. "I used to eat a lot of junk food, but there are plenty of fast food places that offer healthy options, so there's no excuse for eating badly all the time."

But don't expect to see the starlet eating salads when she goes out for date night with boyfriend Kanye West.

""Although, when I go out for dinner, I eat what I want," she told the Closer. "You can't spend your life worrying about calories."

The 31-year-old star has admitted before that she has a difficult time staying in shape and she has often been criticized for her size.

"When I was criticized for it, I said, 'I have cellulite. So what!'" Kardashian told Cosmopolitan UK magazine in January. "I've never claimed to be perfect. It's crazy anyone should assume that just because you're in the spotlight, you're flawless. Sometimes I pig out and I still feel great, and think, 'That was so worth it!'"

The "Keeping Up With the Kardashians" star was sued earlier this year over her endorsement of the over-the-counter diet pill, Quicktrim. Fans were in disbelief that the reality star and her famous sisters had lost weight just from using the over-the-counter pill like they claimed in commercials, magazines and on Twitter, TMZ reported.