The retired footballer, who is married to The Saturdays' singer Frankie, is one of ten celebrities who will enter the Australian jungle on Sunday night's launch show.
"When I talked about it with my wife, she knew I would regret it if I didn't go in," he said.
"She was quite surprised at first because I haven't done anything like this before but she hopes I will enjoy it. I do like playing pranks and sometimes I jump out at people.
"She has told me not to scare people!"
"I have never been approached before but when they did this year, I just thought 'wow,'" he added. "It's such a test and challenge for me. I love the show, my son loves the show and so do my family and friends.
"I want it to happen tomorrow now. All I can think about is the Jungle. Everything is going on around my head and I can't actually believe I managed to get some sleep last night because I can't stop thinking about it."
Wayne, 36, played for England as well as clubs Chelsea, West Ham, Manchester City and Fulham.
However, he's said doing the jungle will be the first time people really get to know him as someone other than an ex-footballer or, in his words, a man who "refused to shake a hand." He famously declined to shake hands with John Terry before a game in 2010, following allegations Terry had an affair with his ex-girlfriend.
An insider previously told The Sun: "Wayne never really sought fame when he was a footballer so it's surprising he agreed to go in the jungle. But ITV believe they've made a real coup getting him on board as he's never discussed the John Terry scandal before."
Frankie, meanwhile, has admitted in the past she'd love to do I'm A Celebrity but having two young children probably rules her out.
"It was the one other show that I would maybe do," she said. "But now I've got the boys, I don't think I would because of three weeks not knowing how they are. Maybe a few years ago I would have done it but not now."
Frankie and Wayne are parents to sons Parker, three, and Carter, one. Wayne also has a son, Jaydon, nine.
Here's the full lineup, all ready to go in their jungle attire.
I'm A Celebrity starts Sunday, 13 November at 9pm on ITV.