Kelly Osbourne was filming her television show Fashion Police in front of a full studio audience when she turned to Melissa Rivers - daughter of comedian Joan - and said "I don't feel good", according to celebrity website TMZ.
The daughter of Sharon and Ozzy then reportedly fell out of her chair before the seizure begun.
An audience member, believed to be an emergency responder, ran up to help Ms Osbourne.
More top news
The launch was made in defiance of United Nations sanctions barring North Korea from using ballistic missile technology.
David Cameron has raised concerns after figures showed 100 babies spent time living behind bars last year.
About 124,000 patients had to wait for at least 12 hours in accident and emergency departments last year, according to an investigation.