'Knocked Up' and "Grey's Anatomy" star Katherine Heigl returns to big-screen romance opposite '300' hunk Gerard Butler in the frothy comedy 'The Ugly Truth,' in theaters July 24 -- but why is she in for a rude awakening?

Katherine plays Abby, a high-strung and romantically challenged morning show producer whose search for Mr. Perfect has left her hopelessly single.

"I think we decided to make Abby just on the cusp of OCD," explains Katherine about her character. "Just a really uptight chick who is super organized, super on top of things, and likes that kind of control in every aspect of her life; she's really great at her job, but she tries to take that professionalism and those organizational skills into dating."

Clearly it's not working. Now, Abby is in for a rude awakening when hardcore TV personality Mike Chadway (Butler) enters the picture and pulls no punches -- on air and off -- about the ugly truth on what makes men and women tick. Will their immediate friction create sparks? Or will someone go down in flames?

Watch ET for more with Katherine and Gerard in our 'The Ugly Truth'!