See Kim Kardashian's Enormous Engagement Ring
PHOTO: Kim Kardashian and Kanye West during Paris Fashion Week, Sept. 29, 2013, in Paris.

Kim Kardashian had a very happy birthday yesterday, capped off with a surprise proposal from her boyfriend, rapper Kanye West. Now, she's showing off her new rock.

"YES!!!" the reality star, 33, tweeted, along with a photo of the sparkler on her left hand.

A Look Back at Kim Kardashian's Loves

West, 36, popped the question at AT&T Park in San Francisco, which is why the baseball scoreboard can be seen in the background of Kardashian's snapshot.

Photos of Kim Kardashian's Road to Marriage

According to E! News, West asked Kardashian's mother, Kris Jenner, for her hand in marriage before proposing with a 15-carat rock from jeweler Lorraine Schwartz.

For the big moment, West had an orchestra play his song "Knock You Down" and made the Jumbotron read, "PLEEEASE MARRY MEEE!!!"

After Kardashian accepted his proposal, her family ran out of the dugout to wish the newly-engaged couple well.

More ABC News