The presenter described Fearne Cotton as "devil woman" in a press interview when she worked for the station four years ago.
"I worked there when I was 19 until I was 21, and then I did an interview in NME where I said a lot of silly things and they let me go," she told Heat.
"It was very sad, as I was into radio. But I hadn't done much press, so I didn't really know what I was doing. I thought I was clued up, but I wasn't."
Oliver currently presents T4 every weekend on Channel 4.