Agron played Monteith’s girlfriend on the show but she was not invited to take part in the tribute episode because her former co-stars and one the co-creators of the show don’t like her. Other former cast members of the hit Fox show were contacted to appear on the tribute episode but Agron was not.
“It’s shocking, because even though she’s not contracted for this season, many other actors returned to pay tribute to Cory…even ones with less of a story connection to Finn than Diana had!” a source told Radar. “Remember, she played his GIRLFRIEND on the series, and was a major part of his storyline.”
According to the source, Monteith’s real-life girlfriend at the time of his death, Lea Michele, and “Glee” co-creator Ryan Murphy "intensely dislike Dianna and have both worked to marginalize her as much as possible."
A conflicting report says Agron is “still very much a part of the Glee family and always welcome." It goes on to say that speculation of troubles between Agron and her former colleagues are "not true at all."
Monteith, 31, was found dead in a Vancouver hotel room in July and the coroner’s report found that he died of “combined heroin and alcohol toxicity.”