The former 30 Rock star plays a college admissions officer who falls for Rudd's character in the upcoming comedy, but Fey was so nervous about stripping down for the role, she used fast food as an incentive to get her through the shoot.
She tells People magazine, "It was a terrifying nightmare. To clarify how much I like this stuff: I had a long-standing agreement with my hair and makeup people that when we shot the last romantic scene, we'd get MCDonald's. That's what kept me going.
"My goal was to get through the scenes without apologising, like, 'It's all going to be fine, and then I'll get a double fish filet. Then I got one and immediately regretted it."