The beauty plays the love interest of Chris Masterson and the pair had to record a number of shots in the bedroom for the film.
But Chris' brother Danny also stars in the movie - and had to watch as his wife-to-be got passionate with his sibling.
Executive producer Sam Hamadeh tells New York Post's gossip column PageSix, "They definitely have a lot of sexual chemistry on screen. It made for some interesting moments on set when Danny had to watch his brother and fiancee go at it."
Phillips and Masterson have been dating since 2004 and announced their engagement earlier this year (09).