Celebrity Parents Justin Timberlake on Expanding His Family: 'I'm Having a Lot of Fun Practicing' "He's a year and a half … want him to stay that size," Timberlake said By Karen Mizoguchi Published on October 24, 2016 07:45 PM Share Tweet Pin Email Photo: Isaiah Trickey/FilmMagic Justin Timberlake and wife Jessica Biel are loving being parents to son Silas Randall. “He’s a year and a half … want him to stay that size,” the Trolls star told Extra‘s Mario Lopez at the animated film’s Los Angeles premiere. Timberlake, 35, and Biel, 34, welcomed their first child in April 2015, and have been enjoying parenthood ever since. So does the couple think of expanding their family? “I’m having a lot of fun practicing,” Timberlake said with a laugh. Josh Brasted/Getty Images The singer/actor may be not planning on Silas having a sibling anytime soon, he’s still mastering the art of fatherhood. “You literally just like wake up and look in the mirror and go, ‘I have no idea what I’m doing,'” he shared on the Today show in October. “It’s humiliating and it’s humbling at the same time.” RELATED VIDEO: Justin Timberlake and Jessica Biel’s Son Is Adorable As for the Timberlake family’s Halloween plans this year, the father of one did not have to think hard about his son’s costume. “I’m trying to put together a family theme, I may pull some rank and see if we can, maybe we’ll be Trolls. Maybe we’ll be some characters from the movie,” he told Lopez. Aww, Silas could dress up like his dad’s character Branch! Trolls opens in theaters Nov. 4.