LOS ANGELES — A transgender child actor will guest star on Wednesday night’s “Modern Family.”

Director Ryan Case has posted on Instagram a picture of herself alongside 8-year-old Jackson Millarker, who identifies as a boy. Case writes that Millarker will play a boy named Tom, who’s a friend of Lily. Lily is the daughter of Cam and Mitchell, played on the show by Eric Stonestreet and Jesse Tyler Ferguson. A spokeswoman for ABC has confirmed Millarker’s appearance.

Case says that Millarker is “just wonderful” and one of many reasons Case loves being a part of the show.

A synopsis of the episode titled “A Stereotypical Day” says Cam and Mitchell overhear Lily insulting Tom and use the moment to teach her a lesson about acceptance.