Let's face it, Knocked Up was the Leslie Mann show! She brought the non-stop laughter portraying Alison Scotts' (Katherine Heigl) married older sister, Debbie. When she wasn't spewing hate filled rants in front of swanky night clubs she couldn't get into she was pointing out Seth Rogen's 'man boobs'. But, she was always there for her little sister. Like when Alison was telling Debbie that she is pregnant and Debbie does what any comforting sister would do and reference the TLC show I Didn't Know I Was Pregnant: "Are you the lady who doesn't realize she's pregnant until she's sitting on the toilet and a kid pops out?!"