Hilary Duff is reportedly stalling on her post-pregnancy body plan because she's so "besotted" with her new family addition.

The blonde beauty and husband Mike Comrie welcomed their son Luca into the world three months ago.

Hilary looked relaxed and slender in a black bikini on a family holiday in Mexico last week and insiders say the actress-and-singer is eager to get a healthy fitness and family balance in place.

"Hilary is sticking to a no-carbs meal plan and has been sweating it out in the gym everyday with Pilates classes," a source told British magazine Closer.

"But she's told friends that she doesn't want to be working out too much, as she wants to spend all her time with Luca. She's absolutely besotted."

Hilary received a barrage of criticism when she was pictured in the skimpy two-piece swimsuit on the vacation.

The 24-year-old star has since hit back at the hateful messages, claiming she's ignoring such negative comments.

“I’m not perfect, but I feel fantastic,” Hilary told In Touch magazine. “This is how it goes for most women – the weight doesn’t fall off overnight.

“I don’t care what people say. I’m not back to where I want to be, but I’m not stressing it.”