If you haven't already, it's definitely time to mark you calendars for May 19th.
Why, you ask? It was just announced that Selena Gomez will perform at this year's Billboard Music Awards, joining an all-star lineup that already includes Justin Bieber, Taylor Swift, and Bruno Mars!
Taylor and Justin are also up for awards in bunch of categories that night -- including Artist of the Year, where they'll face off against One Direction, Rihanna, and Maroon 5.
We can't decide which of these stars we're most excited to see take the stage. How about you?