Jennifer Lopez & Casper Smart: Bookstore with the Twins!

Jennifer Lopez rocks a trendy dress while holding hands with her twins Emme and Max at Barnes & Noble on Saturday (September 14) in Calabasas, Calif.

The 44-year-old American Idol judge was joined by her boyfriend Casper Smart, who showed some support for the New York Yankees.

PHOTOS: Check out the latest pics of Jennifer Lopez

It was recently reported that Jennifer and Taylor Swift will collaborate on a track for Jenifer‘s upcoming album, which drops early next year.

“Both of them are huge fans of each other and excited to work together!” a close source told Us Weekly.

FYI: Jennifer is wearing Jean-Michel Cazabat shoes and Lana Jewelry earrings.

10+ pictures inside of Jennifer Lopez heading to Barnes & Noble with her twins…