Simon's participation on the judging panel had previously been announced.
Terry is an action-movie actor, a sitcom star, a designer of high-end furniture, a human rights activist, a former professional football player, and more. In addition to his role on Brooklyn Nine-Nine, he also appeared in the films Deadpool 2 and Sorry to Bother You.
"I am so proud and honored to join Simon, Mel, Heidi and Howie in hosting the No. 1 alternative series on television," Terry said in a statement.
"NBC's America's Got Talent is a show I love to watch with my family and now to actually be a part of this special edition, The Champions, is more than I could have asked or dreamed. Now America's Got Terry Crews!"
America's Got Talent: The Champions, produced by Syco Entertainment and Fremantle, will air on Monday nights in January and February 2019 in between seasons of The Voice.
The AGT spinoff, which has been hosted by Tyra Banks for the last two seasons, will feature some of the most talented acts from previous seasons of NBC's show as well as memorable and popular acts from international editions. The Got Talent franchise spans 184 countries.
The Champions spinoff will also showcase some of the "wackiest and all-around favorite" contestants from franchise history.
All of these acts will come together to compete for "the ultimate display of talent," according to NBC, and the winning act will receive $1 million.
Howie, Mel B, Heidi and Simon have been serving as judges of the original America's Got Talent series together since Season 11. Before Simon came into the picture as on-air talent, the other three judges sat on the panel with Howard Stern from Season 8 through Season 10.