Kelly Osbourne's Fashion Police co-host Melissa Rivers rushed to her side after she suffered a seizure and collapsed on the set of the show Thursday morning.

Rivers told Entertainment Tonight that during the traumatic event she laid on the ground with Osbourne until help arrived.

"More than anything it was just scary," Melissa says. "I just laid on the ground holding on to her until the paramedics came.

"I just laid on the ground with her until we got the seizure to stop. She was disoriented and I just laid on the ground with her to keep her down because she kept trying to stand up," she adds.

Osbourne wanted to continue filming the episode, but instead was taken to a nearby hospital for observation and tests to determine why she had the seizure.

"I made her look at me," Melissa says. "I said, 'I'm here, stay with me, it's all fine.' I explained where we were."

Kelly was taken out of the studio on a stretcher and had a sheet over her head to shield her from the paparazzi. During her hospital stay she tweeted an update to her fans.

"Thank U all 4 UR beautiful well wishes yes I did have a seizure they are just trying to figure out why?"

Melissa, daughter of Fashion Police regular Joan Rivers, has been filling in on the show for Giuliana Rancic.