Gardiner was replaced by Louie Spence for the 2011 series, but after a drop in ratings, the Australian choreographer was recalled.
Watch our interview with the Dancing on Ice judges:
Speaking about the phonecall, Gardiner said: "I thought it was a joke. I really did. I thought it was someone trying to wind me up."
He also promised that he wouldn't tone down his usual caustic remarks with the contestants.
"I just call it as I see it," he said. "You know what to expect!"
The judge will be joined on this year's panel by Pussycat Doll Ashley Roberts, Robin Cousins and Karen Barber, with whom he famously fell out on the show two years ago.
"Have we had a meeting? We haven't seen each other since the last time I was on the show and we literally just said 'hello' this morning," said Gardiner, when asked about his relationship with Barber.
Meanwhile, Barber merely replied "no comment" when asked for her thoughts on Gardiner's return.
Head judge Cousins laughed: "I think the two years off for Karen have done her good. I've seen a new feisty side to the Barber. Who knows who is going to say what to whom!"
Dancing on Ice returns for its eighth series on Sunday night (January 6) on ITV.
Photo gallery - Dancing on Ice 2013 launch photocall: