Stallone will share a pivotal storyline with Justin Hartley’s character, Kevin, who will spend a part of this season filming the Ron Howard movie mentioned at the end of in the season one finale.
The 71-year-old actor will play Kevin’s co-star and father figure on the set of the fictional film.
Stallone’s casting is somewhat of a reunion for him and This Is Us star Milo Ventimiglia, with whom he co-starred in 2006’s Rocky Balboa, though it is unclear -- and unlikely -- that the two will share any significant screen time together. Fogelman credited Stallone’s previous connection to Ventimiglia as helping to make the casting happen.
“It's nice to know that the material attracts the greats even like Sly. And to know that he'd want to be a part and play with us, it's a very good feeling, so we're thrilled," Ventimiglia told ET following the announcement. "I'm personally excited, too, because his character's involvement gives Jack a lot. Because you imagine if Sylvester Stallone is Kevin's movie idol, where'd he learn that from? Probably from Jack, probably from dad."
Stallone joins a rich stable of past guest stars on the Emmy-nominated series, including Howard, Katie Couric, Katey Sagal, Brad Garrett, Seth Meyers, Jimmi Simpson and Elizabeth Perkins.
This Is Us premieres Tuesday, Sept. 26 at 9 p.m. ET/PT on NBC.