AceShowbiz - Jessica Biel's eldest son is always asking her to voice her characters from children's show "Pete the Cat", even though he has no interest in watching the series for himself.

The actress reveals Silas, six, is well aware of his parents' fame, because he's a big fan of dad Justin Timberlake's voiceover role as Branch in the "Trolls" film franchise, as well as his music, but he refuses to tune into Jessica's Amazon cartoon.

Asked if her children understand what their parents do, Jessica told America's "The Tonight Show Starring Jimmy Fallon", "Silas does definitely with Justin because of Branch. And also his music - whenever he hears daddy's song, he'll go, 'Oh yeah, that's dad. No big deal, whatever'. "

"But the funny thing about 'Pete the Cat' is I tried to get him to watch the show, he will not watch," she smiled. "And yet he says, 'Hey mum, hey mum, do one of those voices from the show' and I'm like, 'But you've never seen the show, you don't even know'. "

"He's just like, 'Just do it, mum', so I'll do one of the voices and he'll be like, 'Cool, mum, cool'. "

Jessica and Justin are also parents to Phineas, 11 months. When asked is Silas and Phineas are "besties," the "Limetown" actress said, "I think they are, I really do and I really was worried you just never know what's going to happen and how your older one is going to feel about the little one. Just think each other are so funny, and it's so amazing to watch."