Blickentstaff ([title of show], The Little Mermaid) will portray a history teacher, with Page (Spider-Man, Cyrano) in a cameo as a homeless man and Zaken (Spring Awakening) as one of Stephen's classmates.
Youtube sensation Tsui has stepped in for Tony Award winner Levi Kreiss (Million Dollar Quartet), who had to withdraw from the film due to scheduling conflicts.
As previously reported, Ripley (Next to Normal, Side Show) will portray the mother of Billy Elliot cast member Myles Erlick, who stars as Stephen. Godspell cast member Uzo Aduba is also part of the film as a cafeteria lady who breaks into song.
"Sing Along," according to a release, "stars a 14-year-old boy living in New York City, with Broadway theaters as his backyard. Deeply introverted and mildly agoraphobic, his love of musicals translate to an overactive imagination, stemmed from his natural creativity. But it leads to trouble in school and more at home, where his naysayer mother crushes his artistic nature and his dream of being on Broadway himself."