Jessica Simpson's fiance was a ''complete hero'' throughout her recent weight loss.

The reality star's partner, Eric Johnson, helped her shed her baby weight after having second son, Ace, in June by helping make healthy meals and exercising alongside her.

A source told OK! magazine: ''Eric has been a complete hero. He even taught himself how to make meals that won't blow her diet and has been by her side throughout most of her workouts. He avoids her yoga sessions because he's not that flexible, but cardio, running, swimming and walking, he's with her all the way.''

Jessica - who also has 19-month-old Max with Eric - had been adhering to a strict Weight Watchers diet since giving birth, having plenty of healthy smoothies, celery sticks with peanut butter and high protein foods, and she is determined to stay in shape for her sons.

The source added: ''They both say Max and Ace deserve the best, so there's no excuse whatsoever for them to not be in the best possible shape, both physically and mentally. Eric always tells her, 'healthy body, healthy mind' and Jessica really believes that. She feels incredible right now and she's been looking amazing.''

However, Jessica will hopefully have skipped her diet today for a traditional turkey dinner as she celebrated Thanksgiving with Eric and his family in Boston.