Dianna Agron Not Welcome At 'Glee' Tribute Show For Cory Monteith: Co-Stars & Creator 'Intensely Dislike' Her

Former Glee cast member Dianna Agron was not invited to appear on the show's tribute episode for the late Cory Monteith, and RadarOnline.com has exclusively learned it's because co-stars and even the co-creator of the show just don't like her.

According to a high-level source on the hit Fox show, other 'Glee' cast members who were not contracted for the current season came back to appear on the tribute episode, but not Agron.

"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!" the source told Radar.

"Remember, she played his GIRLFRIEND on the series, and was a major part of his storyline."

The insider reveals that Monteith's girlfriend, Lea Michele, and co-creator, Ryan Murphy, "intensely dislike Dianna and have both worked to marginalize her as much as possible."

"They never saw her as a team player," the insider added.

"They simply did not want her sharing the glory for this very special episode."

Monteith, 31, was found dead in his Vancouver hotel room on July 13 and it was later determined through an official coroner's report that the Canadian actor died of "combined heroin and alcohol toxicity."

Calls for comment to Agron's rep were unreturned.