The 22-year-old model and wife of tennis champ Andy Roddick will make her feature film debut in Just Go with It, due out on Valentine's Day 2011.
Decker will play Sandler's love interest. To get her attention, he hires Aniston to pose as the wife he's about to divorce and her children as his fake family. The movie's original title was Pretend Wife, according to The Hollywood Reporter.
Decker tweeted excitedly about the project after she arrived in Los Angeles.
"That's why I’m in L.A. now and so excited to get started! The cast has been AMAZING and welcoming. I can't stop gushing about everyone involved!" she writes.
Filming begins in March. Decker previously guest-starred on Ugly Betty.