Selena Gomez, before she took to the stage to perform "Slow Down" on Leno.

There's been QUITE a bit of Selena Gomez action happening as of late, which is, obviously, cool with us. The birthday girl just released her solo debut album, Stars Dance, which includes jams like "Slow Down," "Stars Dance," "Come & Get It," and "Love Will Remember." And, just hours after apparently getting a li'l rowdy at her 21st birthday party, Justin Bieber's maybe-yes-maybe-no GF took to "The Tonight Show With Jay Leno" stage to perform her club-ready "Slow Down." By the look of the twitpic Sel posted right before the performance, girl was REA-DY -- and, most importantly, not showing any signs of a hangover, which is miraculous considering... well, it was her 21st!

Watch Selena Gomez on "The Tonight Show With Jay Leno" after the jump.

Decked in a fierce blue bustier with some massive shoulder pads, Selena tweeted the photo next to the famous "backstage" sign along with the caption, "Performing "Slow Down" on The Tonight Show with @jayleno." We won't spoil the performance for you, but suffice it to say that the lady slayed. Maybe a few extra shots of whiskey actually do the body good! Whaaaat? They say a glass of red wine a day is good for the heart, right?? Why can't the same principal be applied to a coupla bolts of whiskey?! (Just make sure you're 21 or over like Selena, OK?)

+ Watch Selena Gomez perform "Slow Down" on "The Tonight Show With Jay Leno."

Photo credit: @SelenaGomez