Sylvester Stallone will have a guest starring role in season 2 of the NBC television series This Is Us. Showrunner Dan Fogelman made the announcement Thursday during the TCA Summer press tour. Stallone will appear opposite Justin Hartley's character as a co-star in his new film within the series. Stallone previously worked with This Is Us star Milo Ventimiglia in the 2006 film Rocky Balboa, in which Ventimiglia played Rocky's son Robert. It is unlikely that the pair will share any screen time, because the series has multiple timelines. The show was a break out hit in its first season for NBC, while also garnering critical acclaim that includes 11 Emmy nominations.