Stars Reveal: Their Behind-the-Scenes Shots!

Backstage with Katy and Kim! "Necking" on yhe Vampire Diaries set! See what really happens when the cameras aren't rolling in the stars' Twitter pics!

J.LO & NPH

Have you met Barney? Jennifer Lopez has – the actress filmed a guest-starring role on How I Met Your Mother (that's the crew's favorite pub, Maclaren's, in the background), and posed for a shot with Neil Patrick Harris. Jennifer Lopez was really great – hot, cool, and funny. And well prepared! She gave me a few pointers," Harris Tweeted.