Naturally, Diaz and Mann form an unlikely alliance and set their eyes on the blond bombshell for the first time, while Upton flaunts her curves in a sizzling two-piece on the beach.
"Oh my god," Mann gasps when she first sees the 21-year-old model. "Do you think she had that made?" Mann ponders as the camera zooms in on the Sports Illustrated cover girl's enviable derriere.
"No she didn't have that made, when you have a body like that everything fits you well," Diaz quips. "I mean, she's like a perfect 10, lemon tart, double D, obviously."
Things only get more awkward as Diaz tries to chase down Upton, and Mann takes her down in the sand.
"What's going on?" Upton innocently asks as Diaz and Mann are fighting with each other.
Directed by Nick Cassavetes, The Other Woman is slated to hit theaters on Apr. 25.
Upton spoke with E! News in October about joining forces with Diaz and Mann on the flick, saying, "They were the most inspirational and amazing women I had the honor to work with. They were really helpful in my experience with the movie, and I really appreciated all of their advice and all of their encouragement."