Kaley Cuoco
 Kaley Cuoco with Johnny GaleckiInstagram

"The Big Bang Theory" actress Kaley Cuoco, who plays Penny Hofstadter on the CBS comedy, has been accused of displaying diva behaviour on the sets and this is said to have distanced her co-stars, according to a new report.

A source told Star magazine that Cuoco has constant mood swings and she often takes out her irritation on her co-stars, reported Celeb Dirty Laundry, adding that the actress "flips out about makeup, wardrobe, even the catering."

Co-star Mayim Bialik, who plays Amy, won't speak to Cuoco unless necessary, reported the media outlet.

The website further added that Cuoco feels she is in a rut playing Penny on "The Big Bang Theory," and despite her being one of the highest paid actresses on television she hasn't bagged any big budget movies. If Cuoco continues her diva behaviour, she could be written off from the show, believes CDL.

On top of that, Cuoco's personal life hasn't been smooth of late. The actress called it quits with her tennis player husband Ryan Sweeting only after 21 months and her alleged relationship with fellow actor Johnny Galecki also did not work out, reported CDL.

In January In Touch Magazine reported that Galecki and Cuoco started hooking up shortly after she got divorced. "She realized her love for Johnny after her divorce. They're taking things slow because Kaley doesn't want to ruin their friendship if things don't work out again. Kaley and Johnny have no plans to go public until they are both ready," a source told the magazine, reported CDL.

Cuoco slammed these romance rumours in Cosmopolitan's April issue, saying: "Johnny and I are very close now, but the worst part about that is I don't want stories like that, especially during this divorce, to hurt my ex," she said. "We have nods with each other. Johnny and I do this thing like a nod that says, 'I got you. I get it.' "

Also read