“Stranger Things” and “The Lord of the Rings” alum Sean Astin is joining Dwayne Johnson’s “Young Rock” Season 2 in the role of The Rock’s childhood nemesis, Variety has learned exclusively.

A recurring guest star for the NBC comedy’s upcoming second season, Astin will play Dr. Julian Echo in the show’s fast-forwards. Dr. Echo, who had run-ins with Dwayne as a kid, is now a chiropractor from Minnesota who holds a grudge. He reappears two weeks before election day, claiming that Dwayne tried to kill him, a revelation that threatens to derail the Johnson presidential campaign.

Astin’s recent TV credits include playing Bob on “Stranger Things,” as well as guest stints on “The Big Bang Theory,” “Brooklyn Nine-Nine” and “Supergirl.” He also served as narrator on last year’s “Playing with Power: The Nintendo Story.” The actor is also known for his roles in “The Goonies,” “Rudy” and “The Lord of the Rings” trilogy.

Returning on March 15 at 8 p.m., “Young Rock” Season 2 continues with stories inspired by Johnson’s upbringing before turning into The Rock, furthering the storylines from Season 1 while also introducing new chapters. As Dwayne and his family face new challenges and meet new wild characters of professional wrestling, Dwayne contemplates embracing the grind of professional wrestling himself. The show explores the rollercoaster of a childhood that shaped Dwayne into the man he is today and the larger-than-life people he’s met along the way.

“Young Rock” stars Johnson, Joseph Lee Anderson, Stacey Leilua, Ana Tuisila, Adrian Groulx, Bradley Constant, Uli Latukefu, Fasitua Amosa, John Tui and Matthew Willig. As Variety exclusively reported, “Ballers” actor Arlyn Broche is also joining the show for Season 2 as Dany Garcia, the now-media mogul who meets and dates Johnson in college and goes on to become his wife, before the two split romantically but remain strong business partners.

Created by Nahnatchka Khan and Jeff Chiang, “Young Rock” is executive produced by Khan, Chiang, Johnson, Garcia, Jennifer Carreras, Hiram Garcia, Brian Gewirtz and Jeffrey Walker.

“Young Rock” is produced by Universal Television, a division of Universal Studio Group, Seven Bucks Productions and Fierce Baby Productions.

Astin is repped by Stewart Talent, Luber/Roklin and attorney Dave Feldman.