Ms Cruse, who was in Queenstown working with 20th Century Fox to stage the New Zealand premiere of Ice Age 4: Continental Drift on Saturday night, said the Kit Kat Chunky bar was part of a snack selection supplied to her room at The Millennium.
Ms Cruse claimed that as she took her first bite of the bar and began chewing she thought there was a "bug in it" because it was crunchy.
"Unfortunately, I swallowed some," she said.
"It was also like biting down on to an olive stone as I felt my tooth grind.
"I was absolutely aghast as a large piece of glass fell into my hand."
Ms Cruse was "sick with horror" when she realised what had happened and quickly rinsed her mouth.
She noticed blood and claimed to have found a cut of about 1cm in her gum.
After she notified the hotel duty manager, a nurse called Ms Cruse and told her it was unlikely an X-ray would pick up the glass fragment, but there was a risk of internal bleeding.
Ms Cruse said she tried to call Nestle, the manufacturer of the chocolate bar, but its call centre was not staffed over the weekend.
Instead, she took a photograph of the glass and posted it on the company's social networking site - "and put a comment on it".
"It was taken down straight away," she claimed.
Nestle New Zealand media spokesman Maurice Gunnell said last night he was not aware of the complaint, but it was something the company would investigate "thoroughly".
"We take any incident of this nature very seriously," Mr Gunnell said.
