Simpson became a national spokesperson for Weight Watchers following the birth of her first daughter Maxwell Drew Johnson in May.
The Fashion Star judge has since been the subject of tabloid reports claiming that she is hitting the gym more frequently to please the diet company.
"Just so everyone knows ... Weight Watchers hasn't put ANY pressure on me," Simpson clarified on Twitter.
She added of her weight loss progress: "I'm trying to be as healthy as I can be for myself and I feel great!"
Simpson previously promised that she would lose her baby weight responsibly to set a good example for expectant mothers.
Earlier this week, Simpson posted a new photograph of her and fiancé Eric Johnson's daughter Maxwell on her Twitter account.