How a tubby little horse became a star of stage and screen and the toast of NYC

He’s making hay.A local horse named Billy has built quite the resume.

He’s appeared as the carriage horse for Hugh Jackman’s character in “The Greatest Showman;” mesmerized Meryl Streep in “Little Women;” stole Carrie Coon’s heart on the set of “The Gilded Age” and had a scene-stealing run at The Metropolitan Opera House’s “Aida.” The 20-year-old Norwegian Fjord — a stocky, relatively rare breed easily recognizable for their dun-colored coat and striking black-and-white mane and tail — is also the inspiration for the new book “The Star Horse” by Sarah Maslin Nir.“There’s not a lot of horses doing what he does, especially that breed,” Billy’s owner and trainer John Allegra, 72, told The Post of the in-demand steed, who lives on a farm in East Haddam, Connecticut.

Allegra first got Billy when he was 5-years-old with plans of making him a star.Billy cut his teeth attending weddings and town events before going Hollywood.

His big break came around 2017, when he was cast as a carriage horse for Hugh Jackman’s P.T.Barnum character in “The Greatest Showman.” “Billy is the greatest showman — he just [pulled] a carriage in the scene.

He wasn’t one of the circus animals although he could have been,” Allegra quipped.Maslin Nir met Billy in 2019, when she was reporting her book, “Horse Crazy.” She helped lead him on-stage at The Met in Giuseppe Verdi’s opera “Aida” which tells the story of love and betrayal against the backdrop of war.“It was one of those moments as a journalist that’s so unbelievable,” Maslin Nir recalled of the experience.

“It sounds like something out of a children’s fairy tale.” Billy played an Egyptian war horse belonging to the romantic hero.The star horse trotted on stage during the grand Triumphal March in Act II — arguably one of the most famous scenes in operatic history — to the tune of several trumpeters amid a packed stage of around 150 actors carrying spears a...