But the glamour girl has now admitted she went on the show to show the singer she is "not a monster".
In an interview published this week, the mum-of-three revealed she hoped to win back her former husband's approval, saying: "Hopefully he'll watch and see what a decent person I am."
"The girl he married, not the monster. The weird thing is that the Palazzo Versace hotel where all the contestants stay is about 10 minutes from where Pete's family live.
"I hope they will watch the show too and think, 'that is the Kate we know'."
Returning to the jungle – where the couple first met – certainly seems to have put Pete on Katie's mind.
As she chatted to her fellow celebs, the 31-year-old confessed: "I was having a shower and I'm sitting on a rock thinking 'I expect Pete to walk past'."
And she confided to Colin McAllister: "It's so surreal. I've been married, had kids, and been divorced. It's all over. The whole circle and I'm back here. So weird."
She has also revealed how the attraction to her former love - who pulled out of a presenting job on the reality show - was instant. "I knew before I got on the plane."
"I saw a picture and I thought 'Wow'. It was instant. He kept getting his kit off and I though, 'Phwoar. Good old pecs'."
Regardless of Pete's response - he has reportedly told friends he won't be "watching a minute" - it seems Katie will still have to work hard to win the public's approval.
She has been voted to do the next bushtucker trial, Celebrity In A Bottle.
The public's decision follows Katie's nomination to also take part in the Deathly Burrows challenge on Tuesday, an ordeal which saw her pulled out of a tank of water quivering.
She had had to enter a burrow through a mine shaft and break down walls to collect stars to win food for the camp. But as she was washed into the tank, she panicked – as a result of a swimming accident she had when she was young.
In total Katie picked up four stars, winning her fellow contestants a meal of crocodile's feet.