Justin Timberlake is sexy [2] no matter what he does, but there's just something about him in dad mode [3] that really gets our hearts racing. On Friday, the singer treated us to swoon-worthy Instagram video of himself playing with his 3-year-old son Silas's toy guitar. "Dad life. His toys = my toys. #pjmasks," Justin captioned it. If you listen closely, you can also hear what appears to be Silas talking in the background. So cute!