ABC News' Abbie Boudreau reports:

In just six months, singer, reality star and fashion designer Jessica Simpson has lost an astonishing amount of weight.

New photos taken over the weekend are the most revealing look at her post-baby body since Simpson was our special guest on " Good Morning America" in September.

"After having the baby, I've had to really, really focus and start training," Simpson told us then.

Jessica Simpson Guest Hosts 'Good Morning America'

And all that training now appears to be paying off. Simpson says she's shed 60-pounds since giving birth to daughter Maxwell in May. That's just 10 pounds shy of her pre-baby weight.

Simpson, also a Weight Watchers spokesperson, says that in addition to changing her eating habits, her personal trainer is her secret weapon.

Harley Pasternak trains Simpson, along with other stars like Megan Fox and Jennifer Hudson. With a masters of science in exercise physiology and nutritional sciences from the University of Toronto, and an honors degree in kinesiology from the University of Western Ontario, Pasternak is a renowned fitness and nutrition expert and best-selling author.

Pasternak's workout is made up of five phases.

Phase One: Cardio Warm-UP

Phase Two: Upper Body Strength Training

Phase Three: Lower Body Strength Training

Phase Four: Core Training

Phase Five: The Cardio Cool Down

Simpson says she's not giving up on shedding those last few pounds, but she is giving up macaroni and cheese, her favorite pregnancy craving.

SEE ALSO: Jessica Simpson Joins 'GMA' as Special Guest Host