'This Is Us' Star Justin Hartley Says Jack's Death Is Worth the Wait

"This Is Us" star Justin Hartley says people should keep an open mind about how his TV dad, Jack, eventually dies because everything's in play ... including by car accident.

The season 1 finale left fans with a serious cliffhanger. It also pissed off a lot of 'em when it didn't reveal how Jack, played by Milo Ventimiglia, bites it. It's the burning question and while fans now have to wait several months, Justin seems to know already ... and he's talking up the scene a lot ... in a tight white tee.