Sylvester Stallone will guest star in season two of This Is Us. Remember the huge Ron Howard movie that Kevin (Justin Hartley) was offered in the finale? The one that's taking him to L.A. and away from his newly rekindled romance with his ex-wife? Sylvester Stallone will play his co-star.The show's creator Dan Fogelman revealed to reporters at the TCA Press Tour today that Stallone will be a kind of father figure to Kevin, though it's not clear if he means in the fictional movie, or in reality. As for how this came to be, apparently Milo Ventimiglia, who starred with Stallone in Rocky Balboa, made it all happen. We cannot wait to see what his character is like. Stallone probably won't have anything to do with Jack's mysterious death, but at this point, anything is possible.Season two of This Is Us will premiere on NBC Tuesday, September 26.