Kate Hudson and Lea Michele Credit: Pascal Le Segretain/Getty Images; Kevin Mazur/WireImage.com

Filming with Lea Michele hasn't brought Kate Hudson any Glee.

Midway through her six-episode arc as a dance teacher to Michele's character on the Fox hit, Hudson, 33, has found her costar "a total diva," an insider tells Us Weekly. "Kate says Lea is a nightmare. Once, during a technical delay, Lea snapped her fingers and said, 'Let's go. I have plans!'"

Between takes, Hudson (who debuts on the season 4 premiere September 13) hangs out with the whole cast -- except Michele, 26. (Counters Michele's rep, "Lea has had a great time with Kate.")

Adds the source, "Kate's keeping her distance."

Another celebrity guest star to look forward to watching this season on Glee? Sarah Jessica Parker. The Sex and the City actress will star as the sexy song-and-dance mentor of Chris Colfer's character Kurt in episode 3 -- and the two seem to have really hit it off!

"I love her -- I love her!" Colfer, 22, tweeted Aug. 20 about a photo of him and Parker on set. "Can we keep her?"