The actress, who came eighth in the January edition of the Channel 5 show, said that she has heard rumours that Julie Goodyear is a "diva".
"I cannot believe the lineup! Seriously, I thought my house was good back in January, but last night blew me away!" she wrote on her Reveal blog.
"Firstly we had Julie Goodyear. What an amazing housemate. I have heard on the grapevine over the years that she might be a bit of a diva, so that should be interesting!
"My highlight of the evening was of course Martin Kemp going into the house! I sat and watched and nearly cried. He is an amazing man."
Speaking of Goodyear's secret task with Cheryl Fergison, she added: "They did brilliantly. The nerves and feelings you feel going in and being given a task like that to do, it's unbelievably nerve-wracking. It brought back some memories watching tonight."
Cassidy, who recently revealed that 50 Shades of Grey had improved her sex life, was famously given an earpiece by Big Brother and forced to carry out various tasks when she entered the house in January.
Photo gallery - Celebrity Big Brother Summer 2012 launch night: