Even though the cover of this year's Sports Illustrated Swimsuit Issue wasn't supposed to be revealed until midnight on Monday's 'Late Show With David Letterman,' a photo of it was leaked early on Twitter.

"I saw it from my office window," Rana Wardlaw told the Huffington Post. "I work at a media agency called Starcom Worldwide. They unveiled the billboard for a few minutes to tape it for the Letterman Show and then covered it back up. I guess they didn't cover it fast enough!"

Russian model Irina Shayk is the lucky lady gracing the coveted cover. The bodacious 25-year-old has been featured in the past five Swimsuit Issues, though this is her first time on the front. In addition to modeling skimpy swimsuits in the sand, she also has been featured in many high profile ad campaigns including Guess, Armani Exchange, Lacoste and La Perla. Shayk is also currently dating international soccer superstar Cristiano Ronaldo.

See a larger image after the jump.