At the time the 47-year-old blamed his exit on a hot dressing room, but in his new autobiography Gary admits it was because he had been prescribed Tramadol, the same prescription drug that Ant McPartlin became addicted to.
The star said he started taking the drug to get him through Take That’s huge Wonderland tour, but “couldn’t wait to get off it”.
He said: “It was what I was prescribed. I couldn’t wait to get off that. It really made me not me. I wasn’t myself on that.
“James [Gary’s assistant] had caught me about five times that week fainting. I’d just go.
“So basically I’d just look at James and he’d go, ‘He’s going,’ and he’d grab me.
“But I was sat on The One Show, and I just looked at James and thought, ‘I’m going’. And I had to go, and literally as my foot went off the bottom of the screen we went over. Crazy.”
Following his exit from the show, Gary took to Twitter to reassure fans that he was ok, tweeting: “Thank you all for the messages. I’m absolutely fine,” he wrote. “We had a very hot dressing room and I thought I was going to faint on live TV!”
However, his bandmate Howard Donald gave a different version of events, tweeting at the time: “Please don’t worry about Gary. He told me he was touching cloth before he went on. He obviously went off to lay one.”
Ant McPartlin has spoken candidly about his addiction to Tramadol, which led to him entering rehab.
The TV star was first admitted to rehab in June last year after a knee operation left him reliant on the drug, as well as other prescribed painkillers.
“It was getting out of control then. I was taking them whenever willy-nilly. I ran out of my supply very quickly,” he said.
“I was on oral morphine as well. But I finished that off quite quickly. I was drinking far too much – beer, spirits, wine, anything, really.
“I took sleeping pills too – I was prescribed temazepam and diazepam. They’re really strong and addictive. That would knock you out. But with painkillers it’s a very deadly mix.”