Jennifer Lopez hit up a West Hollywood Best Buy to help launch Blackberry's new PlayBook, and as expected, the fans went nuts!

While showing off her toned tummy and wearing glossy pink lipstick, the 41-year-old singer wasn't keeping her appearance a big secret. JLo had tweeted beforehand:

    "I’m headed 2 @BestBuy 2 check out the @BlackBerry #PlayBook. #LOVE? it! Everything I need.. music.. apps.. web AND it fits in my purse!”

Looks like it worked! Find out what else JLo was promoting ... after the jump.