Jessica Biel got her pre-pregnancy figure back by working out "almost every day."

Jessica Biel

Jessica Biel

The 33-year-old actress, who gave birth to son Silas in April with husband Justin Timberlake, was spotted showing off a very svelte figure last week and her trainer admits she has put in a lot of hard work to get back in shape.

Fitness guru Jason Walsh said: "The secret to Jessica's body is her commitment. She enjoys the way she feels when she works out and the results that she sees."

The 'Total Recall' star was a self-confessed gym junkie before giving birth and wasted no time getting back to her intense fitness routine.

A source said: "Working up a sweat was something that she really missed while she was pregnant. It was hard for her to take it easy. She literally couldn't wait to get back in the gym."

The brunette beauty is also following a Paleo-inspired diet, but still wants to set a healthy example for her son.

The insider told OK! magazine: "She works hard and eats right so that she can indulge from time to time. now that she's got a child, she wants to make sure that she instills healthy eating habits, not obsessive ones. She'll be the first one to bake cookies with Silas once he's old enough."