Jessica Biel is a "human vacuum cleaner".

Jessica Biel

Jessica Biel

The 34-year-old actress admitted that she often finishes her 21-month-old son Silas Randall's leftovers, joking that her talent is to make food disappear.

She told PEOPLE: "I'm the human vacuum cleaner at the end of the meal! That is what happens when you are a mom or a dad. You make food, they eat what they eat, and you literally -- as they are running off trying to grab something - you are shoveling the last few bites off of their plate. And that is your lunch... that is your lunch."

However, Jessica insisted that Silas - whose father is Justin Timberlake - likes a wide variety of foods.

She said: "I'm pretty good with vegetables and grains. We actually cook some lamb for Silas, and we do a lot more fish now - but I like vegetables, I like grains, I like quinoa, I like farro - that kind of stuff.

"I'm not saying that I cook that all of the time. A lot of the time we are doing the best that we can - maybe just picking up pre-made stuff from Whole Foods."

Meanwhile, Jessica previously admitted motherhood is the "most challenging job in the world".

She explained: "It's sometimes hard to find the words [to describe motherhood]. So amazing. So lovely. I'm over the moon. Honestly, I would say motherhood [is the most difficult role I've done]. It's probably the most challenging job in the world, but also the most joyous."

And the star has insisted she doesn't want Silas to follow in his parents' footsteps and join the showbiz industry.

She said: "He's probably [inherited] the entertainment gene. He's definitely very charming.

"It's such a challenging existence being an artist. It's hard. I just want him to be happy whatever he does."