The presenter has previously complained about her ill-fated reunion with her former Big Breakfast colleague, saying that it was "not a comfortable environment".
Van Outen is quoted as telling the Daily Mail: "Johnny didn't really welcome me with open arms, in fact he made me feel very uncomfortable.
"He wouldn't let me speak, would tell me when I should and shouldn't speak and would also constantly not mention that we were joint presenters. It was always, 'This is Johnny Vaughan, you are listening to Capital Radio', and there was no mention of my name."
Van Outen added: "I was on the other side of the desk. He had control of the desk and when I would go to speak he would fade my microphone down.
"At the time I was a judge on I'd Do Anything. It was a very popular show but he said that I was not allowed to mention it on the radio because he didn't watch it, even though we were getting loads of calls and texts about it."