Credit: Bjorn Iooss/Sports Illustrated

Va va voom!

Just in time for Valentine's Day, Sports Illustrated revealed the lucky model who will appear on the magazine's coveted swimsuit issue on Monday's The Late Show With David Letterman.

Twenty-five-year-old Russian beauty Irina Shayk took top honors, posing in a barely-there pink and yellow bikini for her first SI cover. Her Hawaii shoot marks Shayk's fifth appearance in the magazine.

Shayk, who dates soccer stud Cristiano Ronaldo, helped present the Top 10 Good Things About Appearing in the Sports Illustrated Swimsuit Edition Monday, and was shocked to see her big reveal.

"There were 10 models there to do the Top 10 List, and nobody knows until the last minute who the cover will be," Shayk said. "And then I saw it, and I couldn't believe it."

Officially on sale Tuesday, the cover was accidentally revealed on Monday afternoon when a New York City office worker snapped a cell phone pic of Shayk's billboard being shot for a Late Show segment.