When J. Lo Met Barney: Singer/actress/diva Jennifer Lopez has already begun filming her buzzed-about guest spot on How I Met Your Mother. On Friday, HIMYM star Neil Patrick Harris TwitPic’d this flick of the “Louboutins” singer on the set of the CBS comedy.

“……Jennifer Lopez was really great – hot, cool, and funny. And well prepared! She gave me a few pointers. Here’s one….” NPH wrote.

Lopez will play self-help author Anita Appleby. She makes it her project to “break” Barney (Neil Patrick Harris) when she learns about his womanizing ways from Robin (Cobie Smulders). Jennifer is expected to make her How I Met Your Mother debut next month.