He began his journey back to London from Brisbane Airport yesterday after he left the show on medical grounds.
In a statement, the 26-year-old admitted he had made a “serious error” taking the pills.
He said: “Shortly after I arrived in Australia I told the production team that I was taking a steroid-based medication that had begun some weeks ago.
“When I started taking this programme of pills it was in preparation for a charity boxing match which, ironically, never took place.”
He added: “Taking these pills was a serious error of judgment, which I hugely regret.
“I have disappointed my family, friends and fans and would like to apologise. I would like to thank ITV for the opportunity and their support, they’re a class act.
“I loved every minute of being in the jungle and wish the remaining contestants the best of luck. Hoping for another shot at it some day.”
He told the Sunday People before flying home: “I screwed up and have some explaining to do.
“I had intended to come off the pills gradually but there was no time to do this before the jungle.
“My admission to the production team I was still taking these pills led to the conclusion it would be unsafe for me to stay, a decision I found extremely hard to stomach.
“I pushed back, but ultimately the show’s duty of care prevailed and bags had to be packed.”