Willow Smith rings in Radio Disney's 15th birthday: Sneak peek behind the scenes!

Selena Gomez helped kick off Radio Disney's 15th birthday celebration this month, and now Willow Smith is joining the party!

The bubbly 10-year-old stopped by the studio for some birthday cake and to shoot an ad for her radio takeover with Ernie D. this Monday (Apr. 18). Zap2it has your first look at the 30-second-spot before it is set to air during Thursday's "American Idol" on FOX.

In the ad, Smith dances to her latest single "21st Century Girl" and strikes a sassy pose. You go, girl!

And in the above clip, Willow describes her perfect birthday cake to Radio Disney host Jake Whetter, and somehow it only makes us love her more. She's not too concerned with how it tastes, but a frosting ponytail is a must.

Zap2it also has exclusive behind-the-scenes photos below, where she works that adorable mug for the camera and enjoys some yummy cake. Plus, check out Willow's 30-second promotional spot before it airs.

Be sure to tune in to the Willow-fied Radio Disney this Monday!