Selena Gomez is sick over her appearance, last night, on Jay Leno's 'Tonight Show.' The actress and singer was rushed to the emergency room after her late night night gig, suffering from nausea and a severe headache, according to TMZ. Gomez was reportedly feeling ill during the taping but stuck it out like a pro -- we had no idea she wasn't feeling as perky as she looked.

The 18-year-old 'Bang Bang Bang' singer spent the night at a Los Angeles hospital where she is still being evaluated and undergoing tests. The teen queen's current condition has yet to be disclosed.

It looks like Gomez and her new beau, Justin Bieber, will have to take it easy this weekend (i.e. no major displays of paparazzi posed PDA). Gomez' doting superstar boyfriend, Bieber, even tweeted, "#getwellselena" in hopes of sparking a Twitter-wide get well card for the ailing songstress.