Co-Executive producer Melissa Rivers (R) answers a question, as host Joan Rivers (C) and co-host Kelly Osbourne listen, at the E! panel for the television show "Fashion Police" during the Television Critics Association summer press tour in Pasadena, California April 15, 2011. REUTERS/Mario Anzuoni

Joan Rivers’ daughter Melissa lay down on the floor with 'Kelly Osbourne after her seizure on Thursday because the singer-turned-reality TV star was "disoriented" and kept attempting to stand up.

Osbourne collapsed while filming her U.S. TV show Fashion Police, and her co-host Rivers and Melissa rushed to her aid.

Melissa Rivers kept her friend calm by "holding on to her", but admits the health scare was traumatizing.

She tells ETOnline.com, "More than anything it was just scary. I just laid on the ground holding on to her until the paramedics came.

"She was disoriented and I just laid on the ground with her to keep her down because she kept trying to stand up.

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

Osbourne wanted to continue working on the show but she was taken to hospital, where doctors placed her under observation to determine why she suffered the seizure.

In a subsequent post on her Twitter.com page, Osbourne explained, "Thank U all 4 UR beautiful well wishes yes I did have a seizure they are just trying to figure out why?"