The 33-year-old singer turned designer showcased her toned body -- and her fiance Eric Johnson's golf club -- in the pics and joked that "if [she's] in a bathing suit" she "should pose proudly."
Simpson's figure has been making headlines ever since she became the spokesperson for Weight Watchers when she was pregnant for the first time in 2012.
In a February Weight Watchers ad, Simpson showcased her 70-pound weight loss in a fitted black dress, joking that she was "too proud to sit down." In her following advertisement, revealed in March, the mother of two said she had a "newfound determination that I'm really proud of."
Simpson and Johnson are parents to daughter Maxwell Drew Johnson (born in May 2012) and son Ace Knute Johnson (born in June, 2013), the two are reportedly getting married in Santa Barbara, Calif. over the 4th of July weekend.