The actor is set to appear in an upcoming episode of the series, which will reunite him with a former co-star.
Annable previously starred on Fox's one-and-done Red Band Society, playing the on-screen love interest of Mandy Moore.
The news broke when Moore and Pearson were spotted filming in New York City on February 11.
TV Line has revealed that Annable is set to appear as Kirby, Kevin's acting teacher, and will have scenes with Moore's Rebecca Pearson.
This Is Us likes to play with time, so we don't have a definite answer on which timeline he will appear in, but based on the set photo from Just Jared, it seems like it will be the past.
Annable is a TV veteran, with TV credits that include Reunion, Heartbeat, The Mick, 666 Park Avenue, What/If, and Yellowstone.