Jennifer Garner  jeans pen  notebook jacket

We love Jen in jeans!

She's got a number one movie at the box office -- Arthur killed it over the weekend -- but Jennifer Garner is still more down-to-earth momma, than high-maintenance movie star.

We caught up with the bare-faced Mrs. Affleck while she was meeting up with a friend for lunch in LA. The actress was armed with a pen and notebook in hand ... is she developing a new movie project, perhaps?

The busy star is currently working on The Odd Life of Timothy Green, costarring Ron Livingston and Diane Wiest.

Check out a very different, and very sexy pic of Jen from Arthur, after the jump ...