Denise Richards played the role of Kelly Van Ryan, who is Suzan's sister. It appears that the film producers knew that Richards was going to be the biggest attraction for "boob enthusiasts," because even when she's not wearing a bikini, she seems to be often dressed in either a sheer one-piece swimsuit or she's entirely topless.
Denise went on to have a great and varied career in Hollywood - she acted alongside actors Dolph Lundgren and Jonathan Lipnicki as a shady FBI agent in the action thriller hit, "Altitude." Even in real life, Richards mirrored her character's bad romantic choices, but she managed to turn her life around after she divorced Charlie Sheen.