Jennifer Lopez Gets Guarded

We caught up with Jennifer Lopez as she left a Best Buy in West Los Angeles on Tuesday -- the singer was there for the Best Buy/Samsung Hope For Children event in support of her Maribel Foundation.

But, we could barely see Jen through all the security! The singer was encouraging fans to come to the event via Twitter -- maybe even more showed up than she expected!

Luckily, we got a pic of Jen inside, where she was wearing a long, gorgeous dress and posed with her sis, Lynda, who co-runs the foundation with Jen (see below). The foundation is dedicated to "the health and well-being of women and children."

It's a cause close to J.Lo's heart -- she's a mother herself. Last weekend, J. Lo broke down on stage in Connecticut. It seemed the tears were from singing her song "If You Had My Love" with a group of dancers dressed as her exes (J. Lo recently split from hubby Marc Anthony), but Jen later attributed the waterworks to seeing her mom in the crowd and a pic of she and her twins projected on a screen above her.