Pakistan, Oct. 12 -- What goes around for Jessica Biel and Justin Timberlake is coming around for their son. Indeed, the 7th Heaven actress and the Grammy winner's son Silas proved he's following in their footsteps with a brief cameo in his mom's new film Matchbox: The Movie, which hit Apple TV Oct. 9. At the end of the film, which also stars John Cena, the 11-year-old appears briefly in a non-speaking role. And while the tween may have had a small part in the project, it's clear he's a star in the making, nonetheless. Prior to the film's release, Biel-also mom to Phineas, six, with Timberlake-reflected on whether Silas took after her or her husband more. "My 11-year-old is a little bit of both," Biel told E! News at the film's premiere O...