Justin Timberlake [1] is one proud dad! The singer stopped by The Tonight Show Starring Jimmy Fallon on Wednesday and graced the world with two precious new photos [2] of his son, Silas. In one snapshot, Justin, who welcomed his son in April with his wife, Jessica Biel [3], is seen holding up the smiling boy close to the camera. In another, Jessica plants a sweet kiss on Silas's cheek as they are both wrapped in towels. Justin, who also performed a "History of Rap" segment with Jimmy [4], gushed about fatherhood, saying, "It is the most insanely amazing, wonderful, unbelievable thing to ever happen to you." Watch the full interview above, then check out Justin and Jimmy doing a "Single Ladies" dance routine at the US Open [5].